src: consolidate XML/JSON exportation

Add new buffer class to consolidate the existing code to export objects
in XML/JSON and use it. We save ~700 LOC with this change.

The rule and set objects are not yet consolidated. It seems this would
require some specific glue code per representation type since lists are
arranged differently.

This also consolidates the tag names, so we make sure the same are used
from XML and JSON by placing them in include/buffer.h.

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

1 files changed, 12 insertions, 44 deletions

diff --git a/src/expr/lookup.c b/src/expr/lookup.c
index 625bc58..29daa30 100644
--- a/src/expr/lookup.c
+++ b/src/expr/lookup.c
@@ -22,6 +22,7 @@
 #include <libnftnl/expr.h>
 #include "data_reg.h"
 #include "expr_ops.h"
+#include <buffer.h>
 
 #ifndef IFNAMSIZ
 #define IFNAMSIZ	16
@@ -208,52 +209,20 @@ nft_rule_expr_lookup_xml_parse(struct nft_rule_expr *e, mxml_node_t *tree,
 }
 
 static int
-nft_rule_expr_lookup_snprintf_json(char *buf, size_t size,
-				   struct nft_rule_expr *e)
+nft_rule_expr_lookup_export(char *buf, size_t size,
+			    struct nft_rule_expr *e, int type)
 {
-	int len = size, offset = 0, ret;
-	struct nft_expr_lookup *l = nft_expr_data(e);
-
-	if (e->flags & (1 << NFT_EXPR_LOOKUP_SET)) {
-		ret = snprintf(buf, len, "\"set\":\"%s\",", l->set_name);
-		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
-	}
-	if (e->flags & (1 << NFT_EXPR_LOOKUP_SREG)) {
-		ret = snprintf(buf + offset, len, "\"sreg\":%u,", l->sreg);
-		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
-	}
-	if (e->flags & (1 << NFT_EXPR_LOOKUP_DREG)) {
-		ret = snprintf(buf + offset, len, "\"dreg\":%u,", l->dreg);
-		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
-	}
-	/* Remove the last comma characther */
-	if (offset > 0)
-		offset--;
-
-	return offset;
-}
-
-static int
-nft_rule_expr_lookup_snprintf_xml(char *buf, size_t size,
-				  struct nft_rule_expr *e)
-{
-	int len = size, offset = 0, ret;
 	struct nft_expr_lookup *l = nft_expr_data(e);
+	NFT_BUF_INIT(b, buf, size);
 
-	if (e->flags & (1 << NFT_EXPR_LOOKUP_SET)) {
-		ret = snprintf(buf, len, "<set>%s</set>", l->set_name);
-		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
-	}
-	if (e->flags & (1 << NFT_EXPR_LOOKUP_SREG)) {
-		ret = snprintf(buf + offset, len, "<sreg>%u</sreg>", l->sreg);
-		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
-	}
-	if (e->flags & (1 << NFT_EXPR_LOOKUP_DREG)) {
-		ret = snprintf(buf + offset, len, "<dreg>%u</dreg>", l->dreg);
-		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
-	}
+	if (e->flags & (1 << NFT_EXPR_LOOKUP_SET))
+		nft_buf_str(&b, type, l->set_name, SET);
+	if (e->flags & (1 << NFT_EXPR_LOOKUP_SREG))
+		nft_buf_u32(&b, type, l->sreg, SREG);
+	if (e->flags & (1 << NFT_EXPR_LOOKUP_DREG))
+		nft_buf_u32(&b, type, l->dreg, DREG);
 
-	return offset;
+	return nft_buf_done(&b);
 }
 
 static int
@@ -284,9 +253,8 @@ nft_rule_expr_lookup_snprintf(char *buf, size_t size, uint32_t type,
 	case NFT_OUTPUT_DEFAULT:
 		return nft_rule_expr_lookup_snprintf_default(buf, size, e);
 	case NFT_OUTPUT_XML:
-		return nft_rule_expr_lookup_snprintf_xml(buf, size, e);
 	case NFT_OUTPUT_JSON:
-		return nft_rule_expr_lookup_snprintf_json(buf, size, e);
+		return nft_rule_expr_lookup_export(buf, size, e, type);
 	default:
 		break;
 	}