netfilter: nf_tables: add NFT_LOGLEVEL_* enumeration and use it

This is internal, not exposed through uapi, and although it maps with
userspace LOG_*, with the introduction of LOGLEVEL_AUDIT we are
incurring in namespace pollution.

This patch adds the NFT_LOGLEVEL_ enumeration and use it from nft_log.

Fixes: 1a893b44 ("netfilter: nf_tables: Add audit support to log statement")
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/uapi/linux/netfilter/nf_tables.h

@@ -1099,9 +1099,31 @@ enum nft_log_attributes {
 #define NFTA_LOG_MAX		(__NFTA_LOG_MAX - 1)
 
 /**
- * LOGLEVEL_AUDIT - a pseudo log level enabling audit logging
- */
-#define LOGLEVEL_AUDIT		8
+ * enum nft_log_level - nf_tables log levels
+ *
+ * @NFT_LOGLEVEL_EMERG: system is unusable
+ * @NFT_LOGLEVEL_ALERT: action must be taken immediately
+ * @NFT_LOGLEVEL_CRIT: critical conditions
+ * @NFT_LOGLEVEL_ERR: error conditions
+ * @NFT_LOGLEVEL_WARNING: warning conditions
+ * @NFT_LOGLEVEL_NOTICE: normal but significant condition
+ * @NFT_LOGLEVEL_INFO: informational
+ * @NFT_LOGLEVEL_DEBUG: debug-level messages
+ * @NFT_LOGLEVEL_AUDIT: enabling audit logging
+ */
+enum nft_log_level {
+	NFT_LOGLEVEL_EMERG,
+	NFT_LOGLEVEL_ALERT,
+	NFT_LOGLEVEL_CRIT,
+	NFT_LOGLEVEL_ERR,
+	NFT_LOGLEVEL_WARNING,
+	NFT_LOGLEVEL_NOTICE,
+	NFT_LOGLEVEL_INFO,
+	NFT_LOGLEVEL_DEBUG,
+	NFT_LOGLEVEL_AUDIT,
+	__NFT_LOGLEVEL_MAX
+};
+#define NFT_LOGLEVEL_MAX	(__NFT_LOGLEVEL_MAX + 1)
 
 /**
  * enum nft_queue_attributes - nf_tables queue expression netlink attributes

net/netfilter/nft_log.c

@@ -111,7 +111,7 @@ static void nft_log_eval(const struct nft_expr *expr,
 	const struct nft_log *priv = nft_expr_priv(expr);
 
 	if (priv->loginfo.type == NF_LOG_TYPE_LOG &&
-	    priv->loginfo.u.log.level == LOGLEVEL_AUDIT) {
+	    priv->loginfo.u.log.level == NFT_LOGLEVEL_AUDIT) {
 		nft_log_eval_audit(pkt);
 		return;
 	}
@@ -166,9 +166,9 @@ static int nft_log_init(const struct nft_ctx *ctx,
 			li->u.log.level =
 				ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));
 		} else {
-			li->u.log.level = LOGLEVEL_WARNING;
+			li->u.log.level = NFT_LOGLEVEL_WARNING;
 		}
-		if (li->u.log.level > LOGLEVEL_AUDIT) {
+		if (li->u.log.level > NFT_LOGLEVEL_AUDIT) {
 			err = -EINVAL;
 			goto err1;
 		}
@@ -196,7 +196,7 @@ static int nft_log_init(const struct nft_ctx *ctx,
 		break;
 	}
 
-	if (li->u.log.level == LOGLEVEL_AUDIT)
+	if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
 		return 0;
 
 	err = nf_logger_find_get(ctx->family, li->type);
@@ -220,7 +220,7 @@ static void nft_log_destroy(const struct nft_ctx *ctx,
 	if (priv->prefix != nft_log_null_prefix)
 		kfree(priv->prefix);
 
-	if (li->u.log.level == LOGLEVEL_AUDIT)
+	if (li->u.log.level == NFT_LOGLEVEL_AUDIT)
 		return;
 
 	nf_logger_put(ctx->family, li->type);