netfilter: nft_log: complete logging support

Use the unified nf_log_packet() interface that allows us explicit
logger selection through the nf_loginfo structure.

If you specify the group attribute, this means you want to receive
logging messages through nfnetlink_log. In that case, the snaplen
and qthreshold attributes allows you to tune internal aspects of
the netlink logging infrastructure.

On the other hand, if the level is specified, then the plain text
format through the kernel logging ring is used instead, which is
also used by default if neither group nor level are indicated.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/uapi/linux/netfilter/nf_tables.h

@@ -697,6 +697,8 @@ enum nft_counter_attributes {
  * @NFTA_LOG_PREFIX: prefix to prepend to log messages (NLA_STRING)
  * @NFTA_LOG_SNAPLEN: length of payload to include in netlink message (NLA_U32)
  * @NFTA_LOG_QTHRESHOLD: queue threshold (NLA_U32)
+ * @NFTA_LOG_LEVEL: log level (NLA_U32)
+ * @NFTA_LOG_FLAGS: logging flags (NLA_U32)
  */
 enum nft_log_attributes {
 	NFTA_LOG_UNSPEC,
@@ -704,6 +706,8 @@ enum nft_log_attributes {
 	NFTA_LOG_PREFIX,
 	NFTA_LOG_SNAPLEN,
 	NFTA_LOG_QTHRESHOLD,
+	NFTA_LOG_LEVEL,
+	NFTA_LOG_FLAGS,
 	__NFTA_LOG_MAX
 };
 #define NFTA_LOG_MAX		(__NFTA_LOG_MAX - 1)

net/netfilter/nft_log.c

 /*
  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
+ * Copyright (c) 2012-2014 Pablo Neira Ayuso <pablo@netfilter.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -41,6 +42,8 @@ static const struct nla_policy nft_log_policy[NFTA_LOG_MAX + 1] = {
 	[NFTA_LOG_PREFIX]	= { .type = NLA_STRING },
 	[NFTA_LOG_SNAPLEN]	= { .type = NLA_U32 },
 	[NFTA_LOG_QTHRESHOLD]	= { .type = NLA_U16 },
+	[NFTA_LOG_LEVEL]	= { .type = NLA_U32 },
+	[NFTA_LOG_FLAGS]	= { .type = NLA_U32 },
 };
 
 static int nft_log_init(const struct nft_ctx *ctx,
@@ -58,18 +61,41 @@ static int nft_log_init(const struct nft_ctx *ctx,
 		if (priv->prefix == NULL)
 			return -ENOMEM;
 		nla_strlcpy(priv->prefix, nla, nla_len(nla) + 1);
-	} else
+	} else {
 		priv->prefix = (char *)nft_log_null_prefix;
+	}
 
-	li->type = NF_LOG_TYPE_ULOG;
+	li->type = NF_LOG_TYPE_LOG;
+	if (tb[NFTA_LOG_LEVEL] != NULL &&
+	    tb[NFTA_LOG_GROUP] != NULL)
+		return -EINVAL;
 	if (tb[NFTA_LOG_GROUP] != NULL)
+		li->type = NF_LOG_TYPE_ULOG;
+
+	switch (li->type) {
+	case NF_LOG_TYPE_LOG:
+		if (tb[NFTA_LOG_LEVEL] != NULL) {
+			li->u.log.level =
+				ntohl(nla_get_be32(tb[NFTA_LOG_LEVEL]));;
+		} else {
+			li->u.log.level = 4;
+		}
+		if (tb[NFTA_LOG_FLAGS] != NULL) {
+			li->u.log.logflags =
+				ntohl(nla_get_be32(tb[NFTA_LOG_FLAGS]));
+		}
+		break;
+	case NF_LOG_TYPE_ULOG:
 		li->u.ulog.group = ntohs(nla_get_be16(tb[NFTA_LOG_GROUP]));
-
-	if (tb[NFTA_LOG_SNAPLEN] != NULL)
-		li->u.ulog.copy_len = ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
-	if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
-		li->u.ulog.qthreshold =
-			ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
+		if (tb[NFTA_LOG_SNAPLEN] != NULL) {
+			li->u.ulog.copy_len =
+				ntohl(nla_get_be32(tb[NFTA_LOG_SNAPLEN]));
+		}
+		if (tb[NFTA_LOG_QTHRESHOLD] != NULL) {
+			li->u.ulog.qthreshold =
+				ntohs(nla_get_be16(tb[NFTA_LOG_QTHRESHOLD]));
+		}
+		break;
 	}
 
 	if (ctx->afi->family == NFPROTO_INET) {
@@ -113,17 +139,33 @@ static int nft_log_dump(struct sk_buff *skb, const struct nft_expr *expr)
 	if (priv->prefix != nft_log_null_prefix)
 		if (nla_put_string(skb, NFTA_LOG_PREFIX, priv->prefix))
 			goto nla_put_failure;
-	if (li->u.ulog.group)
-		if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
-			goto nla_put_failure;
-	if (li->u.ulog.copy_len)
-		if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
-				 htonl(li->u.ulog.copy_len)))
+	switch (li->type) {
+	case NF_LOG_TYPE_LOG:
+		if (nla_put_be32(skb, NFTA_LOG_LEVEL, htonl(li->u.log.level)))
 			goto nla_put_failure;
-	if (li->u.ulog.qthreshold)
-		if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
-				 htons(li->u.ulog.qthreshold)))
+
+		if (li->u.log.logflags) {
+			if (nla_put_be32(skb, NFTA_LOG_FLAGS,
+					 htonl(li->u.log.logflags)))
+				goto nla_put_failure;
+		}
+		break;
+	case NF_LOG_TYPE_ULOG:
+		if (nla_put_be16(skb, NFTA_LOG_GROUP, htons(li->u.ulog.group)))
 			goto nla_put_failure;
+
+		if (li->u.ulog.copy_len) {
+			if (nla_put_be32(skb, NFTA_LOG_SNAPLEN,
+					 htonl(li->u.ulog.copy_len)))
+				goto nla_put_failure;
+		}
+		if (li->u.ulog.qthreshold) {
+			if (nla_put_be16(skb, NFTA_LOG_QTHRESHOLD,
+					 htons(li->u.ulog.qthreshold)))
+				goto nla_put_failure;
+		}
+		break;
+	}
 	return 0;
 
 nla_put_failure: