Support for the nft nth expression within libnftnl.
Signed-off-by: Laura Garcia Liebana <nevola@xxxxxxxxx>
---
include/libnftnl/expr.h | 10 ++
include/linux/netfilter/nf_tables.h | 14 +++
src/Makefile.am | 1 +
src/expr/nth.c | 239 ++++++++++++++++++++++++++++++++++++
src/expr_ops.c | 2 +
5 files changed, 266 insertions(+)
create mode 100644 src/expr/nth.c
diff --git a/include/libnftnl/expr.h b/include/libnftnl/expr.h
index 17f60bd..6d245cd 100644
--- a/include/libnftnl/expr.h
+++ b/include/libnftnl/expr.h
@@ -49,6 +49,11 @@ enum {
};
enum {
+ NFTNL_EXPR_NTH_DREG = NFTNL_EXPR_BASE,
+ NFTNL_EXPR_NTH_DATA,
+};
+
+enum {
NFTNL_EXPR_META_KEY = NFTNL_EXPR_BASE,
NFTNL_EXPR_META_DREG,
NFTNL_EXPR_META_SREG,
@@ -235,6 +240,11 @@ enum {
};
enum {
+ NFT_EXPR_NTH_DREG = NFT_RULE_EXPR_ATTR_BASE,
+ NFT_EXPR_NTH_DATA,
+};
+
+enum {
NFT_EXPR_META_KEY = NFT_RULE_EXPR_ATTR_BASE,
NFT_EXPR_META_DREG,
NFT_EXPR_META_SREG,
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index 01751fa..f90ef48 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -667,6 +667,20 @@ enum nft_exthdr_attributes {
#define NFTA_EXTHDR_MAX (__NFTA_EXTHDR_MAX - 1)
/**
+ * enum nft_nth_attributes - nf_tables nth expression attributes
+ *
+ * @NFTA_NTH_DREG: destination register (NLA_U32)
+ * @NFTA_NTH_DATA: data input (NLA_NESTED)
+ */
+enum nft_nth_attributes {
+ NFTA_NTH_UNSPEC,
+ NFTA_NTH_DREG,
+ NFTA_NTH_DATA,
+ __NFTA_NTH_MAX
+};
+#define NFTA_NTH_MAX (__NFTA_NTH_MAX - 1)
+
+/**
* enum nft_meta_keys - nf_tables meta expression keys
*
* @NFT_META_LEN: packet length (skb->len)
diff --git a/src/Makefile.am b/src/Makefile.am
index 7e580e4..69b61ef 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -38,6 +38,7 @@ libnftnl_la_SOURCES = utils.c \
expr/immediate.c \
expr/match.c \
expr/meta.c \
+ expr/nth.c \
expr/nat.c \
expr/payload.c \
expr/queue.c \
diff --git a/src/expr/nth.c b/src/expr/nth.c
new file mode 100644
index 0000000..4da2968
--- /dev/null
+++ b/src/expr/nth.c
@@ -0,0 +1,239 @@
+/*
+ * (C) 2016 by Laura Garcia <nevola@xxxxxxxxx>
+ *
+ * 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 <string.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <linux/netfilter/nf_tables.h>
+
+#include "internal.h"
+#include <libmnl/libmnl.h>
+#include <libnftnl/expr.h>
+#include <libnftnl/rule.h>
+
+
+struct nftnl_expr_nth {
+ enum nft_registers dreg;
+ union nftnl_data_reg data;
+};
+
+static int
+nftnl_expr_nth_set(struct nftnl_expr *e, uint16_t type,
+ const void *data, uint32_t data_len)
+{
+ struct nftnl_expr_nth *nth = nftnl_expr_data(e);
+
+ switch (type) {
+ case NFTNL_EXPR_NTH_DREG:
+ nth->dreg = *((uint32_t *)data);
+ break;
+ case NFTNL_EXPR_NTH_DATA:
+ memcpy(&nth->data.val, data, data_len);
+ nth->data.len = data_len;
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+static const void *
+nftnl_expr_nth_get(const struct nftnl_expr *e, uint16_t type,
+ uint32_t *data_len)
+{
+ struct nftnl_expr_nth *nth = nftnl_expr_data(e);
+
+ switch (type) {
+ case NFTNL_EXPR_NTH_DREG:
+ *data_len = sizeof(nth->dreg);
+ return &nth->dreg;
+ case NFTNL_EXPR_NTH_DATA:
+ *data_len = nth->data.len;
+ return &nth->data.val;
+ }
+ return NULL;
+}
+
+static int nftnl_expr_nth_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_NTH_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch (type) {
+ case NFTA_NTH_DREG:
+ if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+ abi_breakage();
+ break;
+ case NFTA_NTH_DATA:
+ if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
+ abi_breakage();
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static void
+nftnl_expr_nth_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
+{
+ struct nftnl_expr_nth *nth = nftnl_expr_data(e);
+
+ if (e->flags & (1 << NFTNL_EXPR_NTH_DREG))
+ mnl_attr_put_u32(nlh, NFTA_NTH_DREG, htonl(nth->dreg));
+ if (e->flags & (1 << NFTNL_EXPR_NTH_DATA)) {
+ struct nlattr *nest;
+
+ nest = mnl_attr_nest_start(nlh, NFTA_NTH_DATA);
+ mnl_attr_put(nlh, NFTA_DATA_VALUE, nth->data.len,
+ nth->data.val);
+ mnl_attr_nest_end(nlh, nest);
+ }
+}
+
+static int
+nftnl_expr_nth_parse(struct nftnl_expr *e, struct nlattr *attr)
+{
+ struct nftnl_expr_nth *nth = nftnl_expr_data(e);
+ struct nlattr *tb[NFTA_NTH_MAX+1] = {};
+ int ret = 0;
+
+ if (mnl_attr_parse_nested(attr, nftnl_expr_nth_cb, tb) < 0)
+ return -1;
+
+ if (tb[NFTA_NTH_DREG]) {
+ nth->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_NTH_DREG]));
+ e->flags |= (1 << NFTNL_EXPR_NTH_DREG);
+ }
+ if (tb[NFTA_NTH_DATA]) {
+ ret = nftnl_parse_data(&nth->data, tb[NFTA_NTH_DATA],
+ NULL);
+ e->flags |= (1 << NFTA_NTH_DATA);
+ }
+
+ return ret;
+}
+
+static int nftnl_expr_nth_json_parse(struct nftnl_expr *e, json_t *root,
+ struct nftnl_parse_err *err)
+{
+#ifdef JSON_PARSING
+ struct nftnl_expr_nth *nth = nftnl_expr_data(e);
+ uint32_t reg;
+
+ if (nftnl_jansson_node_exist(root, "dreg")) {
+ if (nftnl_jansson_parse_reg(root, "dreg", NFTNL_TYPE_U32,
+ ®, err) == 0)
+ nftnl_expr_set_u32(e, NFTNL_EXPR_NTH_DREG, reg);
+ }
+
+ if (nftnl_jansson_data_reg_parse(root, "data",
+ &nth->data, err) == DATA_VALUE)
+ e->flags |= (1 << NFTNL_EXPR_NTH_DATA);
+
+ return 0;
+#else
+ errno = EOPNOTSUPP;
+ return -1;
+#endif
+}
+
+
+static int nftnl_expr_nth_xml_parse(struct nftnl_expr *e,
+ mxml_node_t *tree,
+ struct nftnl_parse_err *err)
+{
+#ifdef XML_PARSING
+ struct nftnl_expr_nth *nth = nftnl_expr_data(e);
+ uint32_t dreg;
+
+ if (nftnl_mxml_reg_parse(tree, "dreg", &dreg, MXML_DESCEND_FIRST,
+ NFTNL_XML_OPT, err) == 0)
+ nftnl_expr_set_u32(e, NFTNL_EXPR_NTH_DREG, dreg);
+
+ if (nftnl_mxml_data_reg_parse(tree, "data",
+ &nth->data, NFTNL_XML_MAND,
+ err) == DATA_VALUE)
+ e->flags |= (1 << NFTNL_EXPR_NTH_DATA);
+
+ return 0;
+#else
+ errno = EOPNOTSUPP;
+ return -1;
+#endif
+}
+
+static int
+nftnl_expr_nth_snprintf_default(char *buf, size_t size,
+ const struct nftnl_expr *e)
+{
+ struct nftnl_expr_nth *nth = nftnl_expr_data(e);
+ int len = size, offset = 0, ret;
+
+ ret = nftnl_data_reg_snprintf(buf+offset, len, &nth->data,
+ NFTNL_OUTPUT_DEFAULT, 0,
+ DATA_VALUE);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ ret = snprintf(buf, len, "load reg %u ",
+ nth->dreg);
+ SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
+
+ return offset;
+}
+
+static int nftnl_expr_nth_export(char *buf, size_t size,
+ const struct nftnl_expr *e, int type)
+{
+ struct nftnl_expr_nth *nth = nftnl_expr_data(e);
+
+ NFTNL_BUF_INIT(b, buf, size);
+
+ if (e->flags & (1 << NFTNL_EXPR_NTH_DREG))
+ nftnl_buf_u32(&b, type, nth->dreg, DREG);
+ if (e->flags & (1 << NFTNL_EXPR_NTH_DATA))
+ nftnl_buf_reg(&b, type, &nth->data, DATA_VALUE, DATA);
+
+ return nftnl_buf_done(&b);
+}
+
+static int
+nftnl_expr_nth_snprintf(char *buf, size_t len, uint32_t type,
+ uint32_t flags, const struct nftnl_expr *e)
+{
+ switch (type) {
+ case NFTNL_OUTPUT_DEFAULT:
+ return nftnl_expr_nth_snprintf_default(buf, len, e);
+ case NFTNL_OUTPUT_XML:
+ case NFTNL_OUTPUT_JSON:
+ return nftnl_expr_nth_export(buf, len, e, type);
+ default:
+ break;
+ }
+ return -1;
+}
+
+struct expr_ops expr_ops_nth = {
+ .name = "nth",
+ .alloc_len = sizeof(struct nftnl_expr_nth),
+ .max_attr = NFTA_NTH_MAX,
+ .set = nftnl_expr_nth_set,
+ .get = nftnl_expr_nth_get,
+ .parse = nftnl_expr_nth_parse,
+ .build = nftnl_expr_nth_build,
+ .snprintf = nftnl_expr_nth_snprintf,
+ .xml_parse = nftnl_expr_nth_xml_parse,
+ .json_parse = nftnl_expr_nth_json_parse,
+};
diff --git a/src/expr_ops.c b/src/expr_ops.c
index ae515af..928bb5e 100644
--- a/src/expr_ops.c
+++ b/src/expr_ops.c
@@ -19,6 +19,7 @@ extern struct expr_ops expr_ops_lookup;
extern struct expr_ops expr_ops_masq;
extern struct expr_ops expr_ops_match;
extern struct expr_ops expr_ops_meta;
+extern struct expr_ops expr_ops_nth;
extern struct expr_ops expr_ops_nat;
extern struct expr_ops expr_ops_payload;
extern struct expr_ops expr_ops_redir;
@@ -43,6 +44,7 @@ static struct expr_ops *expr_ops[] = {
&expr_ops_masq,
&expr_ops_match,
&expr_ops_meta,
+ &expr_ops_nth,
&expr_ops_nat,
&expr_ops_payload,
&expr_ops_redir,
--
2.8.1
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