libnftables: Implement JSON output support

Although technically there already is support for JSON output via 'nft
export json' command, it is hardly useable since it exports all the gory
details of nftables VM. Also, libnftables has no control over what is
exported since the content comes directly from libnftnl.

Instead, implement JSON format support for regular 'nft list' commands.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/expression.c b/src/expression.c
index 3c5ea0ff..53fb1811 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -23,6 +23,7 @@
 #include <utils.h>
 #include <list.h>
 #include <erec.h>
+#include <json.h>
 
 struct expr *expr_alloc(const struct location *loc, const struct expr_ops *ops,
 			const struct datatype *dtype, enum byteorder byteorder,
@@ -195,6 +196,7 @@ static const struct expr_ops verdict_expr_ops = {
 	.type		= EXPR_VERDICT,
 	.name		= "verdict",
 	.print		= verdict_expr_print,
+	.json		= verdict_expr_json,
 	.cmp		= verdict_expr_cmp,
 	.clone		= verdict_expr_clone,
 	.destroy	= verdict_expr_destroy,
@@ -319,6 +321,7 @@ static const struct expr_ops constant_expr_ops = {
 	.type		= EXPR_VALUE,
 	.name		= "value",
 	.print		= constant_expr_print,
+	.json		= constant_expr_json,
 	.cmp		= constant_expr_cmp,
 	.clone		= constant_expr_clone,
 	.destroy	= constant_expr_destroy,
@@ -464,6 +467,7 @@ static const struct expr_ops prefix_expr_ops = {
 	.type		= EXPR_PREFIX,
 	.name		= "prefix",
 	.print		= prefix_expr_print,
+	.json		= prefix_expr_json,
 	.set_type	= prefix_expr_set_type,
 	.clone		= prefix_expr_clone,
 	.destroy	= prefix_expr_destroy,
@@ -517,6 +521,7 @@ static const struct expr_ops unary_expr_ops = {
 	.type		= EXPR_UNARY,
 	.name		= "unary",
 	.print		= unary_expr_print,
+	.json		= unary_expr_json,
 	.clone		= unary_expr_clone,
 	.destroy	= unary_expr_destroy,
 };
@@ -592,6 +597,7 @@ static const struct expr_ops binop_expr_ops = {
 	.type		= EXPR_BINOP,
 	.name		= "binop",
 	.print		= binop_expr_print,
+	.json		= binop_expr_json,
 	.clone		= binop_expr_clone,
 	.destroy	= binop_expr_destroy,
 };
@@ -613,6 +619,7 @@ static const struct expr_ops relational_expr_ops = {
 	.type		= EXPR_RELATIONAL,
 	.name		= "relational",
 	.print		= binop_expr_print,
+	.json		= relational_expr_json,
 	.destroy	= binop_expr_destroy,
 };
 
@@ -679,6 +686,7 @@ static const struct expr_ops range_expr_ops = {
 	.type		= EXPR_RANGE,
 	.name		= "range",
 	.print		= range_expr_print,
+	.json		= range_expr_json,
 	.clone		= range_expr_clone,
 	.destroy	= range_expr_destroy,
 	.set_type	= range_expr_set_type,
@@ -763,6 +771,7 @@ static const struct expr_ops concat_expr_ops = {
 	.type		= EXPR_CONCAT,
 	.name		= "concat",
 	.print		= concat_expr_print,
+	.json		= concat_expr_json,
 	.clone		= compound_expr_clone,
 	.destroy	= concat_expr_destroy,
 };
@@ -781,6 +790,7 @@ static const struct expr_ops list_expr_ops = {
 	.type		= EXPR_LIST,
 	.name		= "list",
 	.print		= list_expr_print,
+	.json		= list_expr_json,
 	.clone		= compound_expr_clone,
 	.destroy	= compound_expr_destroy,
 };
@@ -867,6 +877,7 @@ static const struct expr_ops set_expr_ops = {
 	.type		= EXPR_SET,
 	.name		= "set",
 	.print		= set_expr_print,
+	.json		= set_expr_json,
 	.set_type	= set_expr_set_type,
 	.clone		= compound_expr_clone,
 	.destroy	= compound_expr_destroy,
@@ -915,6 +926,7 @@ static const struct expr_ops mapping_expr_ops = {
 	.type		= EXPR_MAPPING,
 	.name		= "mapping",
 	.print		= mapping_expr_print,
+	.json		= mapping_expr_json,
 	.set_type	= mapping_expr_set_type,
 	.clone		= mapping_expr_clone,
 	.destroy	= mapping_expr_destroy,
@@ -959,6 +971,7 @@ static const struct expr_ops map_expr_ops = {
 	.type		= EXPR_MAP,
 	.name		= "map",
 	.print		= map_expr_print,
+	.json		= map_expr_json,
 	.clone		= map_expr_clone,
 	.destroy	= map_expr_destroy,
 };
@@ -1000,6 +1013,7 @@ static const struct expr_ops set_ref_expr_ops = {
 	.type		= EXPR_SET_REF,
 	.name		= "set reference",
 	.print		= set_ref_expr_print,
+	.json		= set_ref_expr_json,
 	.clone		= set_ref_expr_clone,
 	.destroy	= set_ref_expr_destroy,
 };
@@ -1055,6 +1069,7 @@ static const struct expr_ops set_elem_expr_ops = {
 	.name		= "set element",
 	.clone		= set_elem_expr_clone,
 	.print		= set_elem_expr_print,
+	.json		= set_elem_expr_json,
 	.destroy	= set_elem_expr_destroy,
 };