src: add notrack expression

Register this simple expression with no attributes. Make sure libnftnl
doesn't crash when no build and parse indirections are defined, as it
is the case for this expression.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/expr.c b/src/expr.c
index 51413ab70397820f97f9d6036faad8cc48c61520..2779b3c42217dffeac8fab29c7095eeb11261a69 100644 (file)
--- a/src/expr.c
+++ b/src/expr.c
@@ -213,13 +213,15 @@ bool nftnl_expr_cmp(const struct nftnl_expr *e1, const struct nftnl_expr *e2)
 }
 EXPORT_SYMBOL(nftnl_expr_cmp);
 
-void
-nftnl_expr_build_payload(struct nlmsghdr *nlh, struct nftnl_expr *expr)
+void nftnl_expr_build_payload(struct nlmsghdr *nlh, struct nftnl_expr *expr)
 {
        struct nlattr *nest;
 
        mnl_attr_put_strz(nlh, NFTA_EXPR_NAME, expr->ops->name);
 
+       if (!expr->ops->build)
+               return;
+
        nest = mnl_attr_nest_start(nlh, NFTA_EXPR_DATA);
        expr->ops->build(nlh, expr);
        mnl_attr_nest_end(nlh, nest);
@@ -261,6 +263,7 @@ struct nftnl_expr *nftnl_expr_parse(struct nlattr *attr)
                goto err1;
 
        if (tb[NFTA_EXPR_DATA] &&
+           expr->ops->parse &&
            expr->ops->parse(expr, tb[NFTA_EXPR_DATA]) < 0)
                goto err2;
 

diff --git a/src/expr_ops.c b/src/expr_ops.c
index 55748d64989a71f9703b67be60adfe781075f7d8..96b1f8df9d3b9785e1921612c80faddaf95a70b4 100644 (file)
--- a/src/expr_ops.c
+++ b/src/expr_ops.c
@@ -31,6 +31,10 @@ extern struct expr_ops expr_ops_target;
 extern struct expr_ops expr_ops_dynset;
 extern struct expr_ops expr_ops_hash;
 
+static struct expr_ops expr_ops_notrack = {
+       .name   = "notrack",
+};
+
 static struct expr_ops *expr_ops[] = {
        &expr_ops_bitwise,
        &expr_ops_byteorder,
@@ -49,6 +53,7 @@ static struct expr_ops *expr_ops[] = {
        &expr_ops_meta,
        &expr_ops_ng,
        &expr_ops_nat,
+       &expr_ops_notrack,
        &expr_ops_payload,
        &expr_ops_range,
        &expr_ops_redir,