initial version of libnftables

It adds support for table, chain and rule handling.

This also includes expression handling for each rule.

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

1 files changed, 203 insertions, 0 deletions

diff --git a/src/expr/match.c b/src/expr/match.c
new file mode 100644
index 0000000..a9e2dee
--- /dev/null
+++ b/src/expr/match.c
@@ -0,0 +1,203 @@
+/*
+ * (C) 2012 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 "internal.h"
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>	/* for memcpy */
+#include <arpa/inet.h>
+
+#include <libmnl/libmnl.h>
+
+#include <linux/netfilter/nf_tables.h>
+#include <linux/netfilter/x_tables.h>
+
+#include <libnftables/expr.h>
+
+#include "expr_ops.h"
+
+struct nft_expr_match {
+	char		name[XT_EXTENSION_MAXNAMELEN];
+	uint32_t	rev;
+	uint32_t	data_len;
+	const void	*data;
+};
+
+static int
+nft_rule_expr_match_set(struct nft_rule_expr *e, uint16_t type,
+			 const void *data, size_t data_len)
+{
+	struct nft_expr_match *mt = (struct nft_expr_match *)e->data;
+
+	switch(type) {
+	case NFT_EXPR_MT_NAME:
+		memcpy(mt->name, data, XT_EXTENSION_MAXNAMELEN);
+		mt->name[XT_EXTENSION_MAXNAMELEN-1] = '\0';
+		break;
+	case NFT_EXPR_MT_REV:
+		mt->rev = *((uint32_t *)data);
+		break;
+	case NFT_EXPR_MT_INFO:
+		if (mt->data)
+			free((void *)mt->data);
+
+		mt->data = data;
+		mt->data_len = data_len;
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static const void *
+nft_rule_expr_match_get(struct nft_rule_expr *e, uint16_t type,
+			size_t *data_len)
+{
+	struct nft_expr_match *mt = (struct nft_expr_match *)e->data;
+
+	switch(type) {
+	case NFT_EXPR_MT_NAME:
+		if (e->flags & (1 << NFT_EXPR_MT_NAME)) {
+			*data_len = sizeof(mt->name);
+			return mt->name;
+		} else
+			return NULL;
+		break;
+	case NFT_EXPR_MT_REV:
+		if (e->flags & (1 << NFT_EXPR_MT_REV)) {
+			*data_len = sizeof(mt->rev);
+			return &mt->rev;
+		} else
+			return NULL;
+		break;
+	case NFT_EXPR_MT_INFO:
+		if (e->flags & (1 << NFT_EXPR_MT_INFO)) {
+			*data_len = mt->data_len;
+			return mt->data;
+		} else
+			return NULL;
+		break;
+	default:
+		break;
+	}
+	return NULL;
+}
+
+static int nft_rule_expr_match_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_MATCH_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+	case NFTA_MATCH_NAME:
+		if (mnl_attr_validate(attr, MNL_TYPE_NUL_STRING) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFTA_MATCH_REV:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFTA_MATCH_INFO:
+		if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void
+nft_rule_expr_match_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
+{
+	struct nft_expr_match *mt = (struct nft_expr_match *)e->data;
+
+	if (e->flags & (1 << NFT_EXPR_MT_NAME))
+		mnl_attr_put_strz(nlh, NFTA_MATCH_NAME, mt->name);
+	if (e->flags & (1 << NFT_EXPR_MT_REV))
+		mnl_attr_put_u32(nlh, NFTA_MATCH_REV, htonl(mt->rev));
+	if (e->flags & (1 << NFT_EXPR_MT_INFO))
+		mnl_attr_put(nlh, NFTA_MATCH_INFO, XT_ALIGN(mt->data_len), mt->data);
+}
+
+static int nft_rule_expr_match_parse(struct nft_rule_expr *e, struct nlattr *attr)
+{
+	struct nft_expr_match *match = (struct nft_expr_match *)e->data;
+	struct nlattr *tb[NFTA_MATCH_MAX+1] = {};
+
+	if (mnl_attr_parse_nested(attr, nft_rule_expr_match_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_MATCH_NAME]) {
+		snprintf(match->name, XT_EXTENSION_MAXNAMELEN, "%s",
+			 mnl_attr_get_str(tb[NFTA_MATCH_NAME]));
+
+		match->name[XT_EXTENSION_MAXNAMELEN-1] = '\0';
+		e->flags |= (1 << NFTA_MATCH_NAME);
+	}
+
+	if (tb[NFTA_MATCH_REV]) {
+		match->rev = ntohl(mnl_attr_get_u32(tb[NFTA_MATCH_REV]));
+		e->flags |= (1 << NFTA_MATCH_REV);
+	}
+
+	if (tb[NFTA_MATCH_INFO]) {
+		uint32_t len = mnl_attr_get_payload_len(tb[NFTA_MATCH_INFO]);
+		void *match_data;
+
+		if (match->data)
+			free((void *) match->data);
+
+		match_data = calloc(1, len);
+		if (match_data == NULL)
+			return -1;
+
+		memcpy(match_data, mnl_attr_get_payload(tb[NFTA_MATCH_INFO]), len);
+
+		match->data = match_data;
+		match->data_len = len;
+
+		e->flags |= (1 << NFTA_MATCH_INFO);
+	}
+
+	return 0;
+}
+
+static int
+nft_rule_expr_match_snprintf(char *buf, size_t len, struct nft_rule_expr *e)
+{
+	struct nft_expr_match *match = (struct nft_expr_match *)e->data;
+
+	return snprintf(buf, len, "name=%s rev=%u ",
+			match->name, match->rev);
+}
+
+struct expr_ops expr_ops_match = {
+	.name		= "match",
+	.alloc_len	= sizeof(struct nft_expr_match),
+	.max_attr	= NFTA_MATCH_MAX,
+	.set		= nft_rule_expr_match_set,
+	.get		= nft_rule_expr_match_get,
+	.parse		= nft_rule_expr_match_parse,
+	.build		= nft_rule_expr_match_build,
+	.snprintf	= nft_rule_expr_match_snprintf,
+};