expr: payload: Do not print unset values in xml file

It changes the parse and snprintf functions to omit unset values.

Signed-off-by: Ana Rey <anarey@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/expr/payload.c b/src/expr/payload.c
index 6c08e485452303eb5bf80b5ce9f843bb89e3a0f0..78878f3328358259dc77d7965137a7b906992909 100644 (file)
--- a/src/expr/payload.c
+++ b/src/expr/payload.c
@@ -247,32 +247,27 @@ nft_rule_expr_payload_xml_parse(struct nft_rule_expr *e, mxml_node_t *tree,
        uint32_t dreg, offset, len;
 
        if (nft_mxml_reg_parse(tree, "dreg", &dreg, MXML_DESCEND_FIRST,
-                              NFT_XML_MAND, err) != 0)
-               return -1;
-
-       nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_DREG, dreg);
+                              NFT_XML_MAND, err) == 0)
+               nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_DREG, dreg);
 
        base_str = nft_mxml_str_parse(tree, "base", MXML_DESCEND_FIRST,
                                      NFT_XML_MAND, err);
-       if (base_str == NULL)
-               return -1;
-
-       base = nft_str2base(base_str);
-       if (base < 0)
-               return -1;
+       if (base_str != NULL) {
+               base = nft_str2base(base_str);
+               if (base < 0)
+                       return -1;
 
-       nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_BASE, base);
+               nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_BASE, base);
+       }
 
        if (nft_mxml_num_parse(tree, "offset", MXML_DESCEND_FIRST, BASE_DEC,
-                              &offset, NFT_TYPE_U32, NFT_XML_MAND, err) != 0)
-               return -1;
-       nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_OFFSET, offset);
+                              &offset, NFT_TYPE_U32, NFT_XML_MAND, err) == 0)
+               nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_OFFSET, offset);
 
 
        if (nft_mxml_num_parse(tree, "len", MXML_DESCEND_FIRST, BASE_DEC,
-                              &len, NFT_TYPE_U32, NFT_XML_MAND, err) != 0)
-               return -1;
-       nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_LEN, len);
+                              &len, NFT_TYPE_U32, NFT_XML_MAND, err) == 0)
+               nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_LEN, len);
 
        return 0;
 #else
@@ -288,13 +283,24 @@ nft_rule_expr_payload_snprintf_xml(char *buf, size_t len, uint32_t flags,
        struct nft_expr_payload *payload = nft_expr_data(e);
        int size = len, offset = 0, ret;
 
-       ret = snprintf(buf, len, "<dreg>%u</dreg>"
-                                "<offset>%u</offset>"
-                                "<len>%u</len>"
-                                "<base>%s</base>",
-                      payload->dreg, payload->offset, payload->len,
-                      base2str(payload->base));
-       SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       if (e->flags & (1 << NFT_EXPR_PAYLOAD_DREG)) {
+               ret = snprintf(buf, len, "<dreg>%u</dreg>", payload->dreg);
+               SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       }
+       if (e->flags & (1 << NFT_EXPR_PAYLOAD_OFFSET)) {
+               ret = snprintf(buf + offset, len, "<offset>%u</offset>",
+                              payload->offset);
+               SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       }
+       if (e->flags & (1 << NFT_EXPR_PAYLOAD_LEN)) {
+               ret = snprintf(buf + offset, len, "<len>%u</len>", payload->len);
+               SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       }
+       if (e->flags & (1 << NFT_EXPR_PAYLOAD_BASE)) {
+               ret = snprintf(buf + offset, len, "<base>%s</base>",
+                              base2str(payload->base));
+               SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+       }
 
        return offset;
 }