expr: add log expression

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

1 files changed, 281 insertions, 0 deletions

diff --git a/src/expr/log.c b/src/expr/log.c
new file mode 100644
index 0000000..0e35a65
--- /dev/null
+++ b/src/expr/log.c
@@ -0,0 +1,281 @@
+/*
+ * (C) 2012-2013 by 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 as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <linux/netfilter/nf_tables.h>
+
+#include "internal.h"
+#include <libmnl/libmnl.h>
+#include <libnftables/expr.h>
+#include <libnftables/rule.h>
+#include "expr_ops.h"
+
+struct nft_expr_log {
+	uint32_t		group;
+	uint32_t		snaplen;
+	uint32_t		qthreshold;
+	char			*prefix;
+};
+
+static int
+nft_rule_expr_log_set(struct nft_rule_expr *e, uint16_t type,
+		       const void *data, size_t data_len)
+{
+	struct nft_expr_log *log = (struct nft_expr_log *)e->data;
+
+	switch(type) {
+	case NFT_EXPR_LOG_PREFIX:
+		if (log->prefix)
+			free(log->prefix);
+
+		log->prefix = strdup(data);
+		break;
+	case NFT_EXPR_LOG_GROUP:
+		log->group = *((uint32_t *)data);
+		break;
+	case NFT_EXPR_LOG_SNAPLEN:
+		log->snaplen = *((uint32_t *)data);
+		break;
+	case NFT_EXPR_LOG_QTHRESHOLD:
+		log->qthreshold = *((uint32_t *)data);
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static const void *
+nft_rule_expr_log_get(struct nft_rule_expr *e, uint16_t type, size_t *data_len)
+{
+	struct nft_expr_log *log = (struct nft_expr_log *)e->data;
+
+	switch(type) {
+	case NFT_EXPR_LOG_PREFIX:
+		if (e->flags & (1 << NFT_EXPR_LOG_PREFIX))
+			return log->prefix;
+		else
+			return NULL;
+		break;
+	case NFT_EXPR_LOG_GROUP:
+		if (e->flags & (1 << NFT_EXPR_LOG_GROUP))
+			return &log->group;
+		else
+			return NULL;
+		break;
+	case NFT_EXPR_LOG_SNAPLEN:
+		if (e->flags & (1 << NFT_EXPR_LOG_SNAPLEN))
+			return &log->snaplen;
+		else
+			return NULL;
+		break;
+	case NFT_EXPR_LOG_QTHRESHOLD:
+		if (e->flags & (1 << NFT_EXPR_LOG_QTHRESHOLD))
+			return &log->qthreshold;
+		else
+			return NULL;
+		break;
+	default:
+		break;
+	}
+	return NULL;
+}
+
+static int nft_rule_expr_log_cb(const struct nlattr *attr, void *data)
+{
+	const struct nlattr **tb = data;
+	int type = mnl_attr_get_type(attr);
+
+	if (mnl_attr_type_valid(attr, NFTA_LOG_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+	case NFTA_LOG_PREFIX:
+		if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFTA_LOG_GROUP:
+	case NFTA_LOG_SNAPLEN:
+	case NFTA_LOG_QTHRESHOLD:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void
+nft_rule_expr_log_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
+{
+	struct nft_expr_log *log = (struct nft_expr_log *)e->data;
+
+	if (e->flags & (1 << NFT_EXPR_LOG_PREFIX))
+		mnl_attr_put_str(nlh, NFTA_LOG_PREFIX, log->prefix);
+	if (e->flags & (1 << NFT_EXPR_LOG_GROUP))
+		mnl_attr_put_u32(nlh, NFTA_LOG_GROUP, htonl(log->group));
+	if (e->flags & (1 << NFT_EXPR_LOG_SNAPLEN))
+		mnl_attr_put_u32(nlh, NFTA_LOG_SNAPLEN, htonl(log->snaplen));
+	if (e->flags & (1 << NFT_EXPR_LOG_QTHRESHOLD))
+		mnl_attr_put_u32(nlh, NFTA_LOG_QTHRESHOLD, htonl(log->qthreshold));
+}
+
+static int
+nft_rule_expr_log_parse(struct nft_rule_expr *e, struct nlattr *attr)
+{
+	struct nft_expr_log *log = (struct nft_expr_log *)e->data;
+	struct nlattr *tb[NFTA_LOG_MAX+1] = {};
+
+	if (mnl_attr_parse_nested(attr, nft_rule_expr_log_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_LOG_PREFIX]) {
+		if (log->prefix)
+			free(log->prefix);
+
+		log->prefix = strdup(mnl_attr_get_str(tb[NFTA_LOG_PREFIX]));
+		e->flags |= (1 << NFT_EXPR_LOG_GROUP);
+	}
+	if (tb[NFTA_LOG_GROUP]) {
+		log->group = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_GROUP]));
+		e->flags |= (1 << NFT_EXPR_LOG_GROUP);
+	}
+	if (tb[NFTA_LOG_SNAPLEN]) {
+		log->snaplen = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_SNAPLEN]));
+		e->flags |= (1 << NFT_EXPR_LOG_SNAPLEN);
+	}
+	if (tb[NFTA_LOG_QTHRESHOLD]) {
+		log->qthreshold = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_QTHRESHOLD]));
+		e->flags |= (1 << NFT_EXPR_LOG_QTHRESHOLD);
+	}
+
+	return 0;
+}
+
+static int nft_rule_expr_log_xml_parse(struct nft_rule_expr *e, char *xml)
+{
+#ifdef XML_PARSING
+	struct nft_expr_log *log = (struct nft_expr_log *)e->data;
+	mxml_node_t *tree = NULL;
+	mxml_node_t *node = NULL;
+	uint64_t tmp;
+	char *endptr;
+
+	tree = mxmlLoadString(NULL, xml, MXML_OPAQUE_CALLBACK);
+	if (tree == NULL)
+		return -1;
+
+	if (mxmlElementGetAttr(tree, "type") == NULL)
+		goto err;
+
+	if (strcmp("log", mxmlElementGetAttr(tree, "type")) != 0)
+		goto err;
+
+	node = mxmlFindElement(tree, tree, "prefix", NULL, NULL,
+			       MXML_DESCEND_FIRST);
+	if (node == NULL)
+		goto err;
+
+	log->prefix = strdup(node->child->value.opaque);
+	e->flags |= (1 << NFT_EXPR_LOG_PREFIX);
+
+	node = mxmlFindElement(tree, tree, "group", NULL, NULL, MXML_DESCEND);
+	if (node == NULL)
+		goto err;
+
+	tmp = strtoull(node->child->value.opaque, &endptr, 10);
+	if (tmp > UINT32_MAX || tmp < 0 || *endptr)
+		goto err;
+
+	log->group = tmp;
+	e->flags |= (1 << NFT_EXPR_LOG_GROUP);
+
+	node = mxmlFindElement(tree, tree, "snaplen", NULL, NULL,
+			       MXML_DESCEND);
+	if (node == NULL)
+		goto err;
+
+	tmp = strtoull(node->child->value.opaque, &endptr, 10);
+	if (tmp > UINT32_MAX || tmp < 0 || *endptr)
+		goto err;
+
+	log->snaplen = tmp;
+	e->flags |= (1 << NFT_EXPR_LOG_SNAPLEN);
+
+	node = mxmlFindElement(tree, tree, "qthreshold", NULL, NULL,
+			       MXML_DESCEND);
+	if (node == NULL)
+		goto err;
+
+	tmp = strtoull(node->child->value.opaque, &endptr, 10);
+	if (tmp > UINT32_MAX || tmp < 0 || *endptr)
+		goto err;
+
+	log->qthreshold = tmp;
+	e->flags |= (1 << NFT_EXPR_LOG_QTHRESHOLD);
+
+	mxmlDelete(tree);
+	return 0;
+err:
+	errno = EINVAL;
+	mxmlDelete(tree);
+	return -1;
+#else
+	errno = EOPNOTSUPP;
+	return -1;
+#endif
+}
+
+static int
+nft_rule_expr_log_snprintf(char *buf, size_t len, uint32_t type,
+			    uint32_t flags, struct nft_rule_expr *e)
+{
+	struct nft_expr_log *log = (struct nft_expr_log *)e->data;
+
+	switch(type) {
+	case NFT_RULE_O_DEFAULT:
+		return snprintf(buf, len, "prefix=%s group=%u "
+					  "snaplen=%u qthreshold=%u ",
+				log->prefix, log->group,
+				log->snaplen, log->qthreshold);
+	case NFT_RULE_O_XML:
+		return snprintf(buf, len, "<prefix>%s</prefix>"
+					  "<group>%u</group>"
+					  "<snaplen>%u</snaplen>"
+					  "<qthreshold>%u</qthreshold>",
+				log->prefix, log->group,
+				log->snaplen, log->qthreshold);
+	default:
+		break;
+	}
+	return -1;
+}
+
+struct expr_ops expr_ops_log = {
+	.name		= "log",
+	.alloc_len	= sizeof(struct nft_expr_log),
+	.max_attr	= NFTA_LOG_MAX,
+	.set		= nft_rule_expr_log_set,
+	.get		= nft_rule_expr_log_get,
+	.parse		= nft_rule_expr_log_parse,
+	.build		= nft_rule_expr_log_build,
+	.snprintf	= nft_rule_expr_log_snprintf,
+	.xml_parse	= nft_rule_expr_log_xml_parse,
+};