[libnftnl PATCH v3 0/2] Do not print unset value in xml file

[libnftnl PATCH v3 0/2] Do not print unset value in xml file

[Ana Rey]

In this version, I rename some variables, I fix writing errors in the patch
description and I fix wrong indentation.

[Change in v2:]

Hi,
After some advises of Arturo Borrero, I send a previous patch to
'Code refactoring to use nft_rule_expr_set_* functions' patch and v2 of
"Do not print unset values in xml" patch.


Ana Rey (2):
  expr: log: Code refactoring to use nft_rule_expr_set_* functions
  src: expr: log: Do not print unset values in xml.

 src/expr/log.c | 93 ++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 54 insertions(+), 39 deletions(-)

-- 
2.0.0.rc2

[libnftnl PATCH v3 1/2] expr: log: Code refactoring to use nft_rule_expr_set_* functions

[Ana Rey]

Code refactoring to use nft_rule_expr_set_* in parse functions.

Signed-off-by: Ana Rey <anarey@gmail.com>
Suggested-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
---
[Changes in v3:]
Delete uval16 variable name and add qthreshold and group variable name for
code readability reasons. Also, fix writing errors in the patch description.

[Changes in v2:]

Without changes.

 src/expr/log.c | 44 ++++++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/src/expr/log.c b/src/expr/log.c
index a61a8d3..0b7c646 100644
--- a/src/expr/log.c
+++ b/src/expr/log.c
@@ -133,6 +133,10 @@ nft_rule_expr_log_parse(struct nft_rule_expr *e, struct nlattr *attr)
 {
 	struct nft_expr_log *log = nft_expr_data(e);
 	struct nlattr *tb[NFTA_LOG_MAX+1] = {};
+	const char *prefix;
+	uint32_t snaplen;
+	uint16_t group;
+	uint16_t qthreshold;
 
 	if (mnl_attr_parse_nested(attr, nft_rule_expr_log_cb, tb) < 0)
 		return -1;
@@ -141,20 +145,20 @@ nft_rule_expr_log_parse(struct nft_rule_expr *e, struct nlattr *attr)
 		if (log->prefix)
 			xfree(log->prefix);
 
-		log->prefix = strdup(mnl_attr_get_str(tb[NFTA_LOG_PREFIX]));
-		e->flags |= (1 << NFT_EXPR_LOG_PREFIX);
+		prefix = strdup(mnl_attr_get_str(tb[NFTA_LOG_PREFIX]));
+		nft_rule_expr_set_str(e, NFT_EXPR_LOG_PREFIX, prefix);
 	}
 	if (tb[NFTA_LOG_GROUP]) {
-		log->group = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_GROUP]));
-		e->flags |= (1 << NFT_EXPR_LOG_GROUP);
+		group = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_GROUP]));
+		nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, group);
 	}
 	if (tb[NFTA_LOG_SNAPLEN]) {
-		log->snaplen = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_SNAPLEN]));
-		e->flags |= (1 << NFT_EXPR_LOG_SNAPLEN);
+		snaplen = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_SNAPLEN]));
+		nft_rule_expr_set_u32(e, NFT_EXPR_LOG_SNAPLEN, snaplen);
 	}
 	if (tb[NFTA_LOG_QTHRESHOLD]) {
-		log->qthreshold = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_QTHRESHOLD]));
-		e->flags |= (1 << NFT_EXPR_LOG_QTHRESHOLD);
+		qthreshold = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_QTHRESHOLD]));
+		nft_rule_expr_set_u16(e, NFT_EXPR_LOG_QTHRESHOLD, qthreshold);
 	}
 
 	return 0;
@@ -166,7 +170,8 @@ static int nft_rule_expr_log_json_parse(struct nft_rule_expr *e, json_t *root,
 #ifdef JSON_PARSING
 	const char *prefix;
 	uint32_t snaplen;
-	uint16_t uval16;
+	uint16_t group;
+	uint16_t qthreshold;
 
 	prefix = nft_jansson_parse_str(root, "prefix", err);
 	if (prefix == NULL)
@@ -174,11 +179,11 @@ static int nft_rule_expr_log_json_parse(struct nft_rule_expr *e, json_t *root,
 
 	nft_rule_expr_set_str(e, NFT_EXPR_LOG_PREFIX, prefix);
 
-	if (nft_jansson_parse_val(root, "group", NFT_TYPE_U16, &uval16,
+	if (nft_jansson_parse_val(root, "group", NFT_TYPE_U16, &group,
 				  err) < 0)
 		return -1;
 
-	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, uval16);
+	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, group);
 
 	if (nft_jansson_parse_val(root, "snaplen", NFT_TYPE_U32, &snaplen,
 				  err) < 0)
@@ -187,10 +192,10 @@ static int nft_rule_expr_log_json_parse(struct nft_rule_expr *e, json_t *root,
 	nft_rule_expr_set_u32(e, NFT_EXPR_LOG_SNAPLEN, snaplen);
 
 	if (nft_jansson_parse_val(root, "qthreshold", NFT_TYPE_U16,
-				  &uval16, err) < 0)
+				  &qthreshold, err) < 0)
 		return -1;
 
-	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_QTHRESHOLD, uval16);
+	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_QTHRESHOLD, qthreshold);
 
 	return 0;
 #else
@@ -211,30 +216,25 @@ static int nft_rule_expr_log_xml_parse(struct nft_rule_expr *e,
 				    NFT_XML_MAND, err);
 	if (prefix == NULL)
 		return -1;
-
-	log->prefix = strdup(prefix);
-	e->flags |= (1 << NFT_EXPR_LOG_PREFIX);
+	nft_rule_expr_set_str(e, NFT_EXPR_LOG_PREFIX, prefix);
 
 	if (nft_mxml_num_parse(tree, "group", MXML_DESCEND_FIRST, BASE_DEC,
 			       &log->group, NFT_TYPE_U16, NFT_XML_MAND,
 			       err) != 0)
 		return -1;
-
-	e->flags |= (1 << NFT_EXPR_LOG_GROUP);
+	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, log->group);
 
 	if (nft_mxml_num_parse(tree, "snaplen", MXML_DESCEND_FIRST, BASE_DEC,
 			       &log->snaplen, NFT_TYPE_U32, NFT_XML_MAND,
 			       err) != 0)
 		return -1;
-
-	e->flags |= (1 << NFT_EXPR_LOG_SNAPLEN);
+	nft_rule_expr_set_u32(e, NFT_EXPR_LOG_SNAPLEN, log->snaplen);
 
 	if (nft_mxml_num_parse(tree, "qthreshold", MXML_DESCEND_FIRST,
 			       BASE_DEC, &log->qthreshold,
 			       NFT_TYPE_U16, NFT_XML_MAND, err) != 0)
 		return -1;
-
-	e->flags |= (1 << NFT_EXPR_LOG_QTHRESHOLD);
+	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_QTHRESHOLD, log->qthreshold);
 
 	return 0;
 #else
-- 
2.0.0.rc2

[libnftnl PATCH v3 2/2] src: expr: log: Do not print unset values in xml.

[Ana Rey]

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

If we used this rule:
ntt add rule ip test output log

We got this xml file:

<rule><family>ip</family>
<table>test</table>
<chain>output</chain>
<handle>88</handle>
<expr type="log">
	<prefix>(null)</prefix>
	<group>0</group>
	<snaplen>0</snaplen>
	<qthreshold>0</qthreshold>
</expr>
</rule>

And It was imposible import this file.

Now, That rule creates this xml file without null values:

<rule><family>ip</family>
<table>test</table>
<chain>output</chain>
<handle>88</handle>
<expr type="log">
</expr>
</rule>

and It's possible import this xml file.

Signed-off-by: Ana Rey <anarey@gmail.com>
---

[Changes in v3]
Fix wrong indentation.

[Changes in v2]
This patch has some changes that derive from the previous
"src: expr: log: Code refactoring to use nft_rule_expr_set_* functions"
patch.



 src/expr/log.c | 57 ++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 36 insertions(+), 21 deletions(-)

diff --git a/src/expr/log.c b/src/expr/log.c
index 0b7c646..12e9990 100644
--- a/src/expr/log.c
+++ b/src/expr/log.c
@@ -214,27 +214,25 @@ static int nft_rule_expr_log_xml_parse(struct nft_rule_expr *e,
 
 	prefix = nft_mxml_str_parse(tree, "prefix", MXML_DESCEND_FIRST,
 				    NFT_XML_MAND, err);
-	if (prefix == NULL)
-		return -1;
-	nft_rule_expr_set_str(e, NFT_EXPR_LOG_PREFIX, prefix);
+	if (prefix != NULL)
+		nft_rule_expr_set_str(e, NFT_EXPR_LOG_PREFIX, prefix);
 
 	if (nft_mxml_num_parse(tree, "group", MXML_DESCEND_FIRST, BASE_DEC,
 			       &log->group, NFT_TYPE_U16, NFT_XML_MAND,
-			       err) != 0)
-		return -1;
-	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, log->group);
+			       err) == 0)
+		nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, log->group);
 
 	if (nft_mxml_num_parse(tree, "snaplen", MXML_DESCEND_FIRST, BASE_DEC,
 			       &log->snaplen, NFT_TYPE_U32, NFT_XML_MAND,
-			       err) != 0)
-		return -1;
-	nft_rule_expr_set_u32(e, NFT_EXPR_LOG_SNAPLEN, log->snaplen);
-
-	if (nft_mxml_num_parse(tree, "qthreshold", MXML_DESCEND_FIRST,
-			       BASE_DEC, &log->qthreshold,
-			       NFT_TYPE_U16, NFT_XML_MAND, err) != 0)
-		return -1;
-	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_QTHRESHOLD, log->qthreshold);
+			       err) == 0)
+		nft_rule_expr_set_u32(e, NFT_EXPR_LOG_SNAPLEN, log->snaplen);
+
+	if (nft_mxml_num_parse(tree, "qthreshold", MXML_DESCEND_FIRST, BASE_DEC,
+			       &log->qthreshold, NFT_TYPE_U16, NFT_XML_MAND,
+			       err) == 0) {
+		nft_rule_expr_set_u16(e, NFT_EXPR_LOG_QTHRESHOLD,
+				      log->qthreshold);
+	}
 
 	return 0;
 #else
@@ -256,14 +254,31 @@ static int nft_rule_expr_log_snprintf_default(char *buf, size_t len,
 static int nft_rule_expr_log_snprintf_xml(char *buf, size_t size,
 					  struct nft_rule_expr *e)
 {
+	int ret, len = size, offset = 0;
 	struct nft_expr_log *log = nft_expr_data(e);
 
-	return snprintf(buf, size, "<prefix>%s</prefix>"
-				   "<group>%u</group>"
-				   "<snaplen>%u</snaplen>"
-				   "<qthreshold>%u</qthreshold>",
-			log->prefix, log->group,
-			log->snaplen, log->qthreshold);
+	if (e->flags & (1 << NFT_EXPR_LOG_PREFIX)) {
+		ret = snprintf(buf+offset, len, "<prefix>%s</prefix>",
+			       log->prefix);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+	if (e->flags & (1 << NFT_EXPR_LOG_GROUP)) {
+		ret = snprintf(buf+offset, len, "<group>%u</group>",
+			       log->group);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+	if (e->flags & (1 << NFT_EXPR_LOG_SNAPLEN)) {
+		ret = snprintf(buf+offset, len, "<snaplen>%u</snaplen>",
+			       log->snaplen);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+	if (e->flags & (1 << NFT_EXPR_LOG_QTHRESHOLD)) {
+		ret = snprintf(buf+offset, len, "<qthreshold>%u</qthreshold>",
+			       log->qthreshold);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	return offset;
 }
 
 static int nft_rule_expr_log_snprintf_json(char *buf, size_t len,
-- 
2.0.0.rc2

Re: [libnftnl PATCH v3 1/2] expr: log: Code refactoring to use nft_rule_expr_set_* functions

[Pablo Neira Ayuso]

On Mon, Jun 02, 2014 at 02:06:09PM +0200, Ana Rey wrote:
> @@ -211,30 +216,25 @@ static int nft_rule_expr_log_xml_parse(struct nft_rule_expr *e,
>  				    NFT_XML_MAND, err);
>  	if (prefix == NULL)
>  		return -1;
> -
> -	log->prefix = strdup(prefix);
> -	e->flags |= (1 << NFT_EXPR_LOG_PREFIX);
> +	nft_rule_expr_set_str(e, NFT_EXPR_LOG_PREFIX, prefix);
>  
>  	if (nft_mxml_num_parse(tree, "group", MXML_DESCEND_FIRST, BASE_DEC,
>  			       &log->group, NFT_TYPE_U16, NFT_XML_MAND,
                               ^^^^^^^^^^^
                               note this

>  			       err) != 0)
>  		return -1;
> -
> -	e->flags |= (1 << NFT_EXPR_LOG_GROUP);
> +	nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, log->group);

I know Arturo asked for this, but it doesn't make much sense to set
log->group from nft_mxml_num_parse() and then reset it again via
nft_rule_expr_set_u16().

My suggestion is to make something similar to what the _json() parse
function currently do, ie.

        uint16_t group;

        ...
        if (nft_mxml_num_parse(tree, "group", MXML_DESCEND_FIRST,
                               BASE_DEC, &group, NFT_TYPE_U16,
                               NFT_XML_MAND, err) < 0)
                return -1;

        nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, group);

Note that, while at it, we can consolidate the if check to < 0 instead
of != 0 as we do in many other parts of the code.

Please, send me a v4 version.

Regarding the title, I'd suggest: "Use nft_rule_expr_set_* the xml parsing code"

The json chunk below, you can send me in a different patch as a
cleanup. Thanks.

@@ -166,7 +170,8 @@  static int nft_rule_expr_log_json_parse(struct
nft_rule_expr *e, json_t *root,
 #ifdef JSON_PARSING
        const char *prefix;
        uint32_t snaplen;
-       uint16_t uval16;
+       uint16_t group;
+       uint16_t qthreshold;
 
        prefix = nft_jansson_parse_str(root, "prefix", err);
        if (prefix == NULL)
@@ -174,11 +179,11 @@  static int nft_rule_expr_log_json_parse(struct
nft_rule_expr *e, json_t *root,
 
        nft_rule_expr_set_str(e, NFT_EXPR_LOG_PREFIX, prefix);
 
-       if (nft_jansson_parse_val(root, "group", NFT_TYPE_U16,
        &uval16,
+       if (nft_jansson_parse_val(root, "group", NFT_TYPE_U16, &group,
                                  err) < 0)
                return -1;
 
-       nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, uval16);
+       nft_rule_expr_set_u16(e, NFT_EXPR_LOG_GROUP, group);
 
        if (nft_jansson_parse_val(root, "snaplen", NFT_TYPE_U32,
&snaplen,
                                  err) < 0)
@@ -187,10 +192,10 @@  static int nft_rule_expr_log_json_parse(struct
nft_rule_expr *e, json_t *root,
        nft_rule_expr_set_u32(e, NFT_EXPR_LOG_SNAPLEN, snaplen);
 
        if (nft_jansson_parse_val(root, "qthreshold", NFT_TYPE_U16,
-                                 &uval16, err) < 0)
+                                 &qthreshold, err) < 0)
                return -1;
 
-       nft_rule_expr_set_u16(e, NFT_EXPR_LOG_QTHRESHOLD, uval16);
+       nft_rule_expr_set_u16(e, NFT_EXPR_LOG_QTHRESHOLD, qthreshold);
 
        return 0;
 #else