src: add support for nft_redir expression

This patch adds support for the new nft_redir expression.

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 303 insertions, 0 deletions

diff --git a/src/expr/redir.c b/src/expr/redir.c
new file mode 100644
index 0000000..98e8850
--- /dev/null
+++ b/src/expr/redir.c
@@ -0,0 +1,303 @@
+/*
+ * (C) 2014 by Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
+ *
+ * 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.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <inttypes.h>
+
+#include <linux/netfilter/nf_tables.h>
+
+#include "internal.h"
+#include <libmnl/libmnl.h>
+#include <libnftnl/expr.h>
+#include <libnftnl/rule.h>
+#include "expr_ops.h"
+
+struct nft_expr_redir {
+	enum nft_registers sreg_proto_min;
+	enum nft_registers sreg_proto_max;
+	uint32_t	flags;
+};
+
+static int
+nft_rule_expr_redir_set(struct nft_rule_expr *e, uint16_t type,
+			const void *data, uint32_t data_len)
+{
+	struct nft_expr_redir *redir = nft_expr_data(e);
+
+	switch (type) {
+	case NFT_EXPR_REDIR_REG_PROTO_MIN:
+		redir->sreg_proto_min = *((uint32_t *)data);
+		break;
+	case NFT_EXPR_REDIR_REG_PROTO_MAX:
+		redir->sreg_proto_max = *((uint32_t *)data);
+		break;
+	case NFT_EXPR_REDIR_FLAGS:
+		redir->flags = *((uint32_t *)data);
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static const void *
+nft_rule_expr_redir_get(const struct nft_rule_expr *e, uint16_t type,
+			uint32_t *data_len)
+{
+	struct nft_expr_redir *redir = nft_expr_data(e);
+
+	switch (type) {
+	case NFT_EXPR_REDIR_REG_PROTO_MIN:
+		*data_len = sizeof(redir->sreg_proto_min);
+		return &redir->sreg_proto_min;
+	case NFT_EXPR_REDIR_REG_PROTO_MAX:
+		*data_len = sizeof(redir->sreg_proto_max);
+		return &redir->sreg_proto_max;
+	case NFT_EXPR_REDIR_FLAGS:
+		*data_len = sizeof(redir->flags);
+		return &redir->flags;
+	}
+	return NULL;
+}
+
+static int nft_rule_expr_redir_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_REDIR_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch (type) {
+	case NFTA_REDIR_REG_PROTO_MIN:
+	case NFTA_REDIR_REG_PROTO_MAX:
+	case NFTA_REDIR_FLAGS:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+			abi_breakage();
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void
+nft_rule_expr_redir_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
+{
+	struct nft_expr_redir *redir = nft_expr_data(e);
+
+	if (e->flags & (1 << NFT_EXPR_REDIR_REG_PROTO_MIN))
+		mnl_attr_put_u32(nlh, NFTA_REDIR_REG_PROTO_MIN,
+				 htobe32(redir->sreg_proto_min));
+	if (e->flags & (1 << NFT_EXPR_REDIR_REG_PROTO_MAX))
+		mnl_attr_put_u32(nlh, NFTA_REDIR_REG_PROTO_MAX,
+				 htobe32(redir->sreg_proto_max));
+	if (e->flags & (1 << NFT_EXPR_REDIR_FLAGS))
+		mnl_attr_put_u32(nlh, NFTA_REDIR_FLAGS, htobe32(redir->flags));
+}
+
+static int
+nft_rule_expr_redir_parse(struct nft_rule_expr *e, struct nlattr *attr)
+{
+	struct nft_expr_redir *redir = nft_expr_data(e);
+	struct nlattr *tb[NFTA_REDIR_MAX + 1] = {};
+
+	if (mnl_attr_parse_nested(attr, nft_rule_expr_redir_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_REDIR_REG_PROTO_MIN]) {
+		redir->sreg_proto_min =
+			ntohl(mnl_attr_get_u32(tb[NFTA_REDIR_REG_PROTO_MIN]));
+		e->flags |= (1 << NFT_EXPR_REDIR_REG_PROTO_MIN);
+	}
+	if (tb[NFTA_REDIR_REG_PROTO_MAX]) {
+		redir->sreg_proto_max =
+			ntohl(mnl_attr_get_u32(tb[NFTA_REDIR_REG_PROTO_MAX]));
+		e->flags |= (1 << NFT_EXPR_REDIR_REG_PROTO_MAX);
+	}
+	if (tb[NFTA_REDIR_FLAGS]) {
+		redir->flags = be32toh(mnl_attr_get_u32(tb[NFTA_REDIR_FLAGS]));
+		e->flags |= (1 << NFT_EXPR_REDIR_FLAGS);
+	}
+
+	return 0;
+}
+
+static int
+nft_rule_expr_redir_json_parse(struct nft_rule_expr *e, json_t *root,
+			       struct nft_parse_err *err)
+{
+#ifdef JSON_PARSING
+	uint32_t reg, flags;
+
+	if (nft_jansson_parse_reg(root, "sreg_proto_min", NFT_TYPE_U32,
+				  &reg, err) == 0)
+		nft_rule_expr_set_u32(e, NFT_EXPR_REDIR_REG_PROTO_MIN, reg);
+
+	if (nft_jansson_parse_reg(root, "sreg_proto_max", NFT_TYPE_U32,
+				  &reg, err) == 0)
+		nft_rule_expr_set_u32(e, NFT_EXPR_REDIR_REG_PROTO_MAX, reg);
+
+	if (nft_jansson_parse_val(root, "flags", NFT_TYPE_U32, &flags,
+				  err) == 0)
+		nft_rule_expr_set_u32(e, NFT_EXPR_REDIR_FLAGS, flags);
+
+	return 0;
+#else
+	errno = EOPNOTSUPP;
+	return -1;
+#endif
+}
+
+static int
+nft_rule_expr_redir_xml_parse(struct nft_rule_expr *e, mxml_node_t *tree,
+			      struct nft_parse_err *err)
+{
+#ifdef XML_PARSING
+	uint32_t reg, flags;
+
+	if (nft_mxml_reg_parse(tree, "sreg_proto_min", &reg,
+			       MXML_DESCEND, NFT_XML_OPT, err) == 0)
+		nft_rule_expr_set_u32(e, NFT_EXPR_REDIR_REG_PROTO_MIN, reg);
+
+	if (nft_mxml_reg_parse(tree, "sreg_proto_max", &reg,
+			       MXML_DESCEND, NFT_XML_OPT, err) == 0)
+		nft_rule_expr_set_u32(e, NFT_EXPR_REDIR_REG_PROTO_MAX, reg);
+
+	if (nft_mxml_num_parse(tree, "flags", MXML_DESCEND_FIRST, BASE_DEC,
+			       &flags, NFT_TYPE_U32, NFT_XML_OPT, err) == 0)
+		nft_rule_expr_set_u32(e, NFT_EXPR_REDIR_FLAGS, flags);
+
+	return 0;
+#else
+	errno = EOPNOTSUPP;
+	return -1;
+#endif
+}
+
+static int nft_rule_expr_redir_snprintf_json(char *buf, size_t len,
+					     struct nft_rule_expr *e)
+{
+	int ret, size = len, offset = 0;
+	struct nft_expr_redir *redir = nft_expr_data(e);
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_REG_PROTO_MIN)) {
+		ret = snprintf(buf + offset, len, "\"sreg_proto_min\":%u,",
+			       redir->sreg_proto_min);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_REG_PROTO_MAX)) {
+		ret = snprintf(buf + offset, len, "\"sreg_proto_max\":%u,",
+			       redir->sreg_proto_max);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_FLAGS)) {
+		ret = snprintf(buf + offset, len, "\"flags\":%u",
+			       redir->flags);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	return offset;
+}
+
+static int nft_rule_expr_redir_snprintf_xml(char *buf, size_t len,
+					    struct nft_rule_expr *e)
+{
+	int ret, size = len, offset = 0;
+	struct nft_expr_redir *redir = nft_expr_data(e);
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_REG_PROTO_MIN)) {
+		ret = snprintf(buf + offset, len,
+			       "<sreg_proto_min>%u<sreg_proto_min>",
+			       redir->sreg_proto_min);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_REG_PROTO_MAX)) {
+		ret = snprintf(buf + offset, len,
+			       "<sreg_proto_max>%u</sreg_proto_max>",
+			       redir->sreg_proto_max);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_FLAGS)) {
+		ret = snprintf(buf + offset, len, "<flags>%u</flags>",
+			       redir->flags);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	return offset;
+}
+
+static int nft_rule_expr_redir_snprintf_default(char *buf, size_t len,
+						struct nft_rule_expr *e)
+{
+	int ret, size = len, offset = 0;
+	struct nft_expr_redir *redir = nft_expr_data(e);
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_REG_PROTO_MIN)) {
+		ret = snprintf(buf + offset, len, "proto_min reg %u ",
+			       redir->sreg_proto_min);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_REG_PROTO_MAX)) {
+		ret = snprintf(buf + offset, len, "proto_max reg %u ",
+			       redir->sreg_proto_max);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	if (nft_rule_expr_is_set(e, NFT_EXPR_REDIR_FLAGS)) {
+		ret = snprintf(buf + offset , len, "flags 0x%x ",
+			       redir->flags);
+		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+	}
+
+	return 0;
+}
+
+static int
+nft_rule_expr_redir_snprintf(char *buf, size_t len, uint32_t type,
+			     uint32_t flags, struct nft_rule_expr *e)
+{
+	switch (type) {
+	case NFT_OUTPUT_DEFAULT:
+		return nft_rule_expr_redir_snprintf_default(buf, len, e);
+	case NFT_OUTPUT_XML:
+		return nft_rule_expr_redir_snprintf_xml(buf, len, e);
+	case NFT_OUTPUT_JSON:
+		return nft_rule_expr_redir_snprintf_json(buf, len, e);
+	default:
+		break;
+	}
+	return -1;
+}
+
+struct expr_ops expr_ops_redir = {
+	.name		= "redir",
+	.alloc_len	= sizeof(struct nft_expr_redir),
+	.max_attr	= NFTA_REDIR_MAX,
+	.set		= nft_rule_expr_redir_set,
+	.get		= nft_rule_expr_redir_get,
+	.parse		= nft_rule_expr_redir_parse,
+	.build		= nft_rule_expr_redir_build,
+	.snprintf	= nft_rule_expr_redir_snprintf,
+	.xml_parse	= nft_rule_expr_redir_xml_parse,
+	.json_parse	= nft_rule_expr_redir_json_parse,
+};
+
+static void __init expr_redir_init(void)
+{
+	nft_expr_ops_register(&expr_ops_redir);
+}