This patch adds userspace support to nft_masq, the new expression to perform
masquerade.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@xxxxxxxxx>
---
include/libnftnl/expr.h | 5 +
include/linux/netfilter/nf_tables.h | 14 ++
src/Makefile.am | 1
src/expr/masq.c | 210 +++++++++++++++++++++++++++++++++++
4 files changed, 230 insertions(+)
create mode 100644 src/expr/masq.c
diff --git a/include/libnftnl/expr.h b/include/libnftnl/expr.h
index b493ba8..e599082 100644
--- a/include/libnftnl/expr.h
+++ b/include/libnftnl/expr.h
@@ -155,6 +155,11 @@ enum {
NFT_EXPR_QUEUE_TOTAL,
NFT_EXPR_QUEUE_FLAGS,
};
+
+enum {
+ NFT_EXPR_MASQ_FLAGS = NFT_RULE_EXPR_ATTR_BASE,
+};
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index c000947..9bbcb7b 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -785,6 +785,7 @@ enum nft_nat_types {
* @NFTA_NAT_REG_ADDR_MAX: source register of address range end (NLA_U32: nft_registers)
* @NFTA_NAT_REG_PROTO_MIN: source register of proto range start (NLA_U32: nft_registers)
* @NFTA_NAT_REG_PROTO_MAX: source register of proto range end (NLA_U32: nft_registers)
+ * @NFTA_NAT_FLAGS: additional NAT configuration (NF_NAT_RANGE_*) (NLA_U32)
*/
enum nft_nat_attributes {
NFTA_NAT_UNSPEC,
@@ -794,8 +795,21 @@ enum nft_nat_attributes {
NFTA_NAT_REG_ADDR_MAX,
NFTA_NAT_REG_PROTO_MIN,
NFTA_NAT_REG_PROTO_MAX,
+ NFTA_NAT_FLAGS,
__NFTA_NAT_MAX
};
#define NFTA_NAT_MAX (__NFTA_NAT_MAX - 1)
+/**
+ * enum nft_masq_attributes - nf_tables masquerade expression attributes
+ *
+ * @NFTA_MASQ_FLAGS: additional masquerade configuration (NF_NAT_RANGE_*) (NLA_U32)
+ */
+enum nft_masq_attributes {
+ NFTA_MASQ_FLAGS,
+ __NFTA_MASQ_MAX
+};
+#define NFTA_MASQ_MAX (__NFTA_MASQ_MAX - 1)
+
+
#endif /* _LINUX_NF_TABLES_H */
diff --git a/src/Makefile.am b/src/Makefile.am
index 047bf01..d57ff96 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -35,6 +35,7 @@ libnftnl_la_SOURCES = utils.c \
expr/queue.c \
expr/reject.c \
expr/target.c \
+ expr/masq.c \
expr/data_reg.h \
libnftnl.map \
expr_ops.h \
diff --git a/src/expr/masq.c b/src/expr/masq.c
new file mode 100644
index 0000000..568191e
--- /dev/null
+++ b/src/expr/masq.c
@@ -0,0 +1,210 @@
+/*
+ * (C) 2012 by Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
+ *
+ * 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 <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_masq {
+ uint32_t flags;
+};
+
+static int
+nft_rule_expr_masq_set(struct nft_rule_expr *e, uint16_t type,
+ const void *data, uint32_t data_len)
+{
+ struct nft_expr_masq *masq = nft_expr_data(e);
+
+ switch (type) {
+ case NFT_EXPR_MASQ_FLAGS:
+ masq->flags = *((uint32_t *)data);
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+static const void *
+nft_rule_expr_masq_get(const struct nft_rule_expr *e, uint16_t type,
+ uint32_t *data_len)
+{
+ struct nft_expr_masq *masq = nft_expr_data(e);
+
+ switch (type) {
+ case NFT_EXPR_MASQ_FLAGS:
+ *data_len = sizeof(masq->flags);
+ return &masq->flags;
+ }
+ return NULL;
+}
+
+static int nft_rule_expr_masq_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_MASQ_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch (type) {
+ case NFTA_MASQ_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_masq_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
+{
+ struct nft_expr_masq *masq = nft_expr_data(e);
+
+ if (e->flags & (1 << NFT_EXPR_MASQ_FLAGS))
+ mnl_attr_put_u32(nlh, NFTA_MASQ_FLAGS, htobe32(masq->flags));
+}
+
+static int
+nft_rule_expr_masq_parse(struct nft_rule_expr *e, struct nlattr *attr)
+{
+ struct nft_expr_masq *masq = nft_expr_data(e);
+ struct nlattr *tb[NFTA_MASQ_MAX+1] = {};
+
+ if (mnl_attr_parse_nested(attr, nft_rule_expr_masq_cb, tb) < 0)
+ return -1;
+
+ if (tb[NFTA_MASQ_FLAGS]) {
+ masq->flags = be32toh(mnl_attr_get_u32(tb[NFTA_MASQ_FLAGS]));
+ e->flags |= (1 << NFT_EXPR_MASQ_FLAGS);
+ }
+
+ return 0;
+}
+
+static int
+nft_rule_expr_masq_json_parse(struct nft_rule_expr *e, json_t *root,
+ struct nft_parse_err *err)
+{
+#ifdef JSON_PARSING
+ uint32_t flags;
+
+ if (nft_jansson_parse_val(root, "flags", NFT_TYPE_U32, &flags,
+ err) == 0)
+ nft_rule_expr_set_u32(e, NFT_EXPR_MASQ_FLAGS, flags);
+
+ return 0;
+#else
+ errno = EOPNOTSUPP;
+ return -1;
+#endif
+}
+
+static int
+nft_rule_expr_masq_xml_parse(struct nft_rule_expr *e, mxml_node_t *tree,
+ struct nft_parse_err *err)
+{
+#ifdef XML_PARSING
+ uint32_t flags;
+
+ if (nft_mxml_num_parse(tree, "flags", MXML_DESCEND_FIRST, BASE_DEC,
+ &flags, NFT_TYPE_U32, NFT_XML_MAND, err) == 0)
+ nft_rule_expr_set_u32(e, NFT_EXPR_MASQ_FLAGS, flags);
+
+ return 0;
+#else
+ errno = EOPNOTSUPP;
+ return -1;
+#endif
+}
+static int nft_rule_expr_masq_snprintf_json(char *buf, size_t len,
+ struct nft_rule_expr *e)
+{
+ int ret, size = len, offset = 0;
+ struct nft_expr_masq *masq = nft_expr_data(e);
+
+ if (e->flags & (1 << NFT_EXPR_MASQ_FLAGS)) {
+ ret = snprintf(buf + offset, len, "\"flags\":%u", masq->flags);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+ }
+
+ return offset;
+}
+
+static int nft_rule_expr_masq_snprintf_xml(char *buf, size_t len,
+ struct nft_rule_expr *e)
+{
+ int ret, size = len, offset = 0;
+ struct nft_expr_masq *masq = nft_expr_data(e);
+
+ if (e->flags & (1 << NFT_EXPR_MASQ_FLAGS)) {
+ ret = snprintf(buf + offset, len, "<flags>%u</flags>",
+ masq->flags);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+ }
+
+ return offset;
+}
+
+static int nft_rule_expr_masq_snprintf_default(char *buf, size_t len,
+ struct nft_rule_expr *e)
+{
+ struct nft_expr_masq *masq = nft_expr_data(e);
+
+ return snprintf(buf, len, " flags %u ",
+ masq->flags);
+}
+
+static int nft_rule_expr_masq_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_masq_snprintf_default(buf, len, e);
+ case NFT_OUTPUT_XML:
+ return nft_rule_expr_masq_snprintf_xml(buf, len, e);
+ case NFT_OUTPUT_JSON:
+ return nft_rule_expr_masq_snprintf_json(buf, len, e);
+ default:
+ break;
+ }
+ return -1;
+}
+
+struct expr_ops expr_ops_masq = {
+ .name = "masq",
+ .alloc_len = sizeof(struct nft_expr_masq),
+ .max_attr = NFTA_MASQ_MAX,
+ .set = nft_rule_expr_masq_set,
+ .get = nft_rule_expr_masq_get,
+ .parse = nft_rule_expr_masq_parse,
+ .build = nft_rule_expr_masq_build,
+ .snprintf = nft_rule_expr_masq_snprintf,
+ .xml_parse = nft_rule_expr_masq_xml_parse,
+ .json_parse = nft_rule_expr_masq_json_parse,
+};
+
+static void __init expr_masq_init(void)
+{
+ nft_expr_ops_register(&expr_ops_masq);
+}
--
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