[nft PATCH 2/2] datatype: Describe rt symbol tables

[Phil Sutter <phil@nwl.cc>]

Implement a symbol_table_print() wrapper for the run-time populated
rt_symbol_tables which formats output similar to expr_describe() and
includes the data source.

Since these tables reside in struct output_ctx there is no implicit
connection between data type and therefore providing callbacks for
relevant datat types which feed the data into said wrapper is a simpler
solution than extending expr_describe() itself.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 include/datatype.h |  3 +++
 src/ct.c           |  7 +++++++
 src/datatype.c     | 34 ++++++++++++++++++++++++++++++++++
 src/meta.c         |  7 +++++++
 src/rt.c           |  7 +++++++
 5 files changed, 58 insertions(+)

diff --git a/include/datatype.h b/include/datatype.h
index 09a7894567e4d..c4d6282d6f591 100644
--- a/include/datatype.h
+++ b/include/datatype.h
@@ -252,6 +252,9 @@ extern void symbol_table_print(const struct symbol_table *tbl,
 
 extern struct symbol_table *rt_symbol_table_init(const char *filename);
 extern void rt_symbol_table_free(const struct symbol_table *tbl);
+extern void rt_symbol_table_describe(struct output_ctx *octx, const char *name,
+				     const struct symbol_table *tbl,
+				     const struct datatype *type);
 
 extern const struct datatype invalid_type;
 extern const struct datatype verdict_type;
diff --git a/src/ct.c b/src/ct.c
index ebfd90a1ab0d3..6793464859cad 100644
--- a/src/ct.c
+++ b/src/ct.c
@@ -216,10 +216,17 @@ static struct error_record *ct_label_type_parse(struct parse_ctx *ctx,
 	return NULL;
 }
 
+static void ct_label_type_describe(struct output_ctx *octx)
+{
+	rt_symbol_table_describe(octx, CONNLABEL_CONF,
+				 octx->tbl.ct_label, &ct_label_type);
+}
+
 const struct datatype ct_label_type = {
 	.type		= TYPE_CT_LABEL,
 	.name		= "ct_label",
 	.desc		= "conntrack label",
+	.describe	= ct_label_type_describe,
 	.byteorder	= BYTEORDER_HOST_ENDIAN,
 	.size		= CT_LABEL_BIT_SIZE,
 	.basetype	= &bitmask_type,
diff --git a/src/datatype.c b/src/datatype.c
index 4d867798222be..3b19ae8ef52d8 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -946,6 +946,33 @@ void rt_symbol_table_free(const struct symbol_table *tbl)
 	free_const(tbl);
 }
 
+void rt_symbol_table_describe(struct output_ctx *octx, const char *name,
+			      const struct symbol_table *tbl,
+			      const struct datatype *type)
+{
+	char *path = NULL;
+	FILE *f;
+
+	if (!tbl || !tbl->symbols[0].identifier)
+		return;
+
+	f = open_iproute2_db(name, &path);
+	if (f)
+		fclose(f);
+	if (!path && asprintf(&path, "%s%s",
+			      name[0] == '/' ? "" : "unknown location of ",
+			      name) < 0)
+		return;
+
+	nft_print(octx, "\npre-defined symbolic constants from %s ", path);
+	if (tbl->base == BASE_DECIMAL)
+		nft_print(octx, "(in decimal):\n");
+	else
+		nft_print(octx, "(in hexadecimal):\n");
+	symbol_table_print(tbl, type, type->byteorder, octx);
+	free(path);
+}
+
 void mark_table_init(struct nft_ctx *ctx)
 {
 	ctx->output.tbl.mark = rt_symbol_table_init("rt_marks");
@@ -968,10 +995,17 @@ static struct error_record *mark_type_parse(struct parse_ctx *ctx,
 	return symbolic_constant_parse(ctx, sym, ctx->tbl->mark, res);
 }
 
+static void mark_type_describe(struct output_ctx *octx)
+{
+	rt_symbol_table_describe(octx, "rt_marks",
+				 octx->tbl.mark, &mark_type);
+}
+
 const struct datatype mark_type = {
 	.type		= TYPE_MARK,
 	.name		= "mark",
 	.desc		= "packet mark",
+	.describe	= mark_type_describe,
 	.size		= 4 * BITS_PER_BYTE,
 	.byteorder	= BYTEORDER_HOST_ENDIAN,
 	.basetype	= &integer_type,
diff --git a/src/meta.c b/src/meta.c
index 6f76f0033a630..eca8dac72098a 100644
--- a/src/meta.c
+++ b/src/meta.c
@@ -346,10 +346,17 @@ static struct error_record *devgroup_type_parse(struct parse_ctx *ctx,
 	return symbolic_constant_parse(ctx, sym, ctx->tbl->devgroup, res);
 }
 
+static void devgroup_type_describe(struct output_ctx *octx)
+{
+	rt_symbol_table_describe(octx, "group",
+				 octx->tbl.devgroup, &devgroup_type);
+}
+
 const struct datatype devgroup_type = {
 	.type		= TYPE_DEVGROUP,
 	.name		= "devgroup",
 	.desc		= "devgroup name",
+	.describe	= devgroup_type_describe,
 	.byteorder	= BYTEORDER_HOST_ENDIAN,
 	.size		= 4 * BITS_PER_BYTE,
 	.basetype	= &integer_type,
diff --git a/src/rt.c b/src/rt.c
index 3ee710ddc05b5..d8f3352f4b4a7 100644
--- a/src/rt.c
+++ b/src/rt.c
@@ -45,10 +45,17 @@ static struct error_record *realm_type_parse(struct parse_ctx *ctx,
 	return symbolic_constant_parse(ctx, sym, ctx->tbl->realm, res);
 }
 
+static void realm_type_describe(struct output_ctx *octx)
+{
+	rt_symbol_table_describe(octx, "rt_realms",
+				 octx->tbl.realm, &realm_type);
+}
+
 const struct datatype realm_type = {
 	.type		= TYPE_REALM,
 	.name		= "realm",
 	.desc		= "routing realm",
+	.describe	= realm_type_describe,
 	.byteorder	= BYTEORDER_HOST_ENDIAN,
 	.size		= 4 * BITS_PER_BYTE,
 	.basetype	= &integer_type,
-- 
2.43.0