meta: add parse and build userdata interface

Add support for meta userdata area.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/src/expression.c b/src/expression.c
index a7bbde7eec1ac43ae72920bdda0287a109083ad0..a79c6f55a54829593f1d0025f7c74c5429a30378 100644 (file)
--- a/src/expression.c
+++ b/src/expression.c
@@ -1226,8 +1226,8 @@ const struct expr_ops *expr_ops(const struct expr *e)
 const struct expr_ops *expr_ops_by_type(enum expr_types etype)
 {
        switch (etype) {
-       case EXPR_PAYLOAD:
-               return &payload_expr_ops;
+       case EXPR_PAYLOAD: return &payload_expr_ops;
+       case EXPR_META: return &meta_expr_ops;
        default:
                break;
        }

diff --git a/src/meta.c b/src/meta.c
index 796d8e9414868d21beaf3cbf7707bfad990285ef..135f84b51c55574ae20e59f7514310afea0d651d 100644 (file)
--- a/src/meta.c
+++ b/src/meta.c
@@ -807,6 +807,55 @@ static void meta_expr_pctx_update(struct proto_ctx *ctx,
        }
 }
 
+#define NFTNL_UDATA_META_KEY 0
+#define NFTNL_UDATA_META_MAX 1
+
+static int meta_expr_build_udata(struct nftnl_udata_buf *udbuf,
+                                const struct expr *expr)
+{
+       nftnl_udata_put_u32(udbuf, NFTNL_UDATA_META_KEY, expr->meta.key);
+
+       return 0;
+}
+
+static int meta_parse_udata(const struct nftnl_udata *attr, void *data)
+{
+       const struct nftnl_udata **ud = data;
+       uint8_t type = nftnl_udata_type(attr);
+       uint8_t len = nftnl_udata_len(attr);
+
+       switch (type) {
+       case NFTNL_UDATA_META_KEY:
+               if (len != sizeof(uint32_t))
+                       return -1;
+               break;
+       default:
+               return 0;
+       }
+
+       ud[type] = attr;
+       return 0;
+}
+
+static struct expr *meta_expr_parse_udata(const struct nftnl_udata *attr)
+{
+       const struct nftnl_udata *ud[NFTNL_UDATA_META_MAX + 1] = {};
+       uint32_t key;
+       int err;
+
+       err = nftnl_udata_parse(nftnl_udata_get(attr), nftnl_udata_len(attr),
+                               meta_parse_udata, ud);
+       if (err < 0)
+               return NULL;
+
+       if (!ud[NFTNL_UDATA_META_KEY])
+               return NULL;
+
+       key = nftnl_udata_get_u32(ud[NFTNL_UDATA_META_KEY]);
+
+       return meta_expr_alloc(&internal_location, key);
+}
+
 const struct expr_ops meta_expr_ops = {
        .type           = EXPR_META,
        .name           = "meta",
@@ -815,6 +864,8 @@ const struct expr_ops meta_expr_ops = {
        .cmp            = meta_expr_cmp,
        .clone          = meta_expr_clone,
        .pctx_update    = meta_expr_pctx_update,
+       .build_udata    = meta_expr_build_udata,
+       .parse_udata    = meta_expr_parse_udata,
 };
 
 struct expr *meta_expr_alloc(const struct location *loc, enum nft_meta_keys key)