expr: Add tproxy support

Signed-off-by: Máté Eckl <ecklm94@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

3 files changed, 208 insertions, 0 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index c66a257..fc03661 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -45,6 +45,7 @@ libnftnl_la_SOURCES = utils.c		\
 		      expr/meta.c	\
 		      expr/numgen.c	\
 		      expr/nat.c	\
+		      expr/tproxy.c	\
 		      expr/objref.c	\
 		      expr/payload.c	\
 		      expr/queue.c	\
diff --git a/src/expr/tproxy.c b/src/expr/tproxy.c
new file mode 100644
index 0000000..6fae172
--- /dev/null
+++ b/src/expr/tproxy.c
@@ -0,0 +1,205 @@
+/*
+ * Copyright (c) 2018 Máté Eckl <ecklm94@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 "internal.h"
+
+#include <stdio.h>
+#include <stdint.h>
+#include <limits.h>
+#include <string.h>
+#include <errno.h>
+#include <arpa/inet.h>
+#include <libmnl/libmnl.h>
+#include <linux/netfilter/nf_tables.h>
+#include <libnftnl/expr.h>
+#include <libnftnl/rule.h>
+
+struct nftnl_expr_tproxy {
+	enum nft_registers sreg_addr;
+	enum nft_registers sreg_port;
+	int                family;
+};
+
+static int
+nftnl_expr_tproxy_set(struct nftnl_expr *e, uint16_t type,
+		      const void *data, uint32_t data_len)
+{
+	struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
+
+	switch(type) {
+	case NFTNL_EXPR_TPROXY_FAMILY:
+		tproxy->family = *((uint32_t *)data);
+		break;
+	case NFTNL_EXPR_TPROXY_REG_ADDR:
+		tproxy->sreg_addr = *((uint32_t *)data);
+		break;
+	case NFTNL_EXPR_TPROXY_REG_PORT:
+		tproxy->sreg_port = *((uint32_t *)data);
+		break;
+	default:
+		return -1;
+	}
+
+	return 0;
+}
+
+static const void *
+nftnl_expr_tproxy_get(const struct nftnl_expr *e, uint16_t type,
+		      uint32_t *data_len)
+{
+	struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
+
+	switch(type) {
+	case NFTNL_EXPR_TPROXY_FAMILY:
+		*data_len = sizeof(tproxy->family);
+		return &tproxy->family;
+	case NFTNL_EXPR_TPROXY_REG_ADDR:
+		*data_len = sizeof(tproxy->sreg_addr);
+		return &tproxy->sreg_addr;
+	case NFTNL_EXPR_TPROXY_REG_PORT:
+		*data_len = sizeof(tproxy->sreg_port);
+		return &tproxy->sreg_port;
+	}
+	return NULL;
+}
+
+static int nftnl_expr_tproxy_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_TPROXY_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+	case NFTA_TPROXY_FAMILY:
+	case NFTA_TPROXY_REG_ADDR:
+	case NFTA_TPROXY_REG_PORT:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+			abi_breakage();
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static int
+nftnl_expr_tproxy_parse(struct nftnl_expr *e, struct nlattr *attr)
+{
+	struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
+	struct nlattr *tb[NFTA_TPROXY_MAX + 1] = {};
+
+	if (mnl_attr_parse_nested(attr, nftnl_expr_tproxy_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_TPROXY_FAMILY]) {
+		tproxy->family = ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_FAMILY]));
+		e->flags |= (1 << NFTNL_EXPR_TPROXY_FAMILY);
+	}
+	if (tb[NFTA_TPROXY_REG_ADDR]) {
+		tproxy->sreg_addr =
+			ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_REG_ADDR]));
+		e->flags |= (1 << NFTNL_EXPR_TPROXY_REG_ADDR);
+	}
+	if (tb[NFTA_TPROXY_REG_PORT]) {
+		tproxy->sreg_port =
+			ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_REG_PORT]));
+		e->flags |= (1 << NFTNL_EXPR_TPROXY_REG_PORT);
+	}
+
+	return 0;
+}
+
+static void
+nftnl_expr_tproxy_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
+{
+	struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
+
+	if (e->flags & (1 << NFTNL_EXPR_TPROXY_FAMILY))
+		mnl_attr_put_u32(nlh, NFTA_TPROXY_FAMILY, htonl(tproxy->family));
+
+	if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR))
+		mnl_attr_put_u32(nlh, NFTA_TPROXY_REG_ADDR,
+				 htonl(tproxy->sreg_addr));
+
+	if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT))
+		mnl_attr_put_u32(nlh, NFTA_TPROXY_REG_PORT,
+				 htonl(tproxy->sreg_port));
+}
+
+static int
+nftnl_expr_tproxy_snprintf_default(char *buf, size_t size,
+				const struct nftnl_expr *e)
+{
+	struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
+	int remain = size, offset = 0, ret = 0;
+
+	if (tproxy->family != NFTA_TPROXY_UNSPEC) {
+		ret = snprintf(buf + offset, remain, "%s ",
+			       nftnl_family2str(tproxy->family));
+		SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+	}
+
+	if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR)) {
+		ret = snprintf(buf + offset, remain,
+			       "addr reg %u ", tproxy->sreg_addr);
+		SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+	}
+
+	if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT)) {
+		ret = snprintf(buf + offset, remain,
+			       "port reg %u ", tproxy->sreg_port);
+		SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+	}
+
+	return offset;
+}
+
+static int
+nftnl_expr_tproxy_snprintf(char *buf, size_t size, uint32_t type,
+			uint32_t flags, const struct nftnl_expr *e)
+{
+	switch (type) {
+	case NFTNL_OUTPUT_DEFAULT:
+		return nftnl_expr_tproxy_snprintf_default(buf, size, e);
+	default:
+		break;
+	}
+	return -1;
+}
+
+static bool nftnl_expr_tproxy_cmp(const struct nftnl_expr *e1,
+			       const struct nftnl_expr *e2)
+{
+	struct nftnl_expr_tproxy *n1 = nftnl_expr_data(e1);
+	struct nftnl_expr_tproxy *n2 = nftnl_expr_data(e2);
+	bool eq = true;
+
+	if (e1->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR))
+		eq &= (n1->sreg_addr == n2->sreg_addr);
+	if (e1->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT))
+		eq &= (n1->sreg_port == n2->sreg_port);
+	if (e1->flags & (1 << NFTNL_EXPR_TPROXY_FAMILY))
+		eq &= (n1->family == n2->family);
+
+	return eq;
+}
+
+struct expr_ops expr_ops_tproxy = {
+	.name		= "tproxy",
+	.alloc_len	= sizeof(struct nftnl_expr_tproxy),
+	.max_attr	= NFTA_TPROXY_MAX,
+	.cmp		= nftnl_expr_tproxy_cmp,
+	.set		= nftnl_expr_tproxy_set,
+	.get		= nftnl_expr_tproxy_get,
+	.parse		= nftnl_expr_tproxy_parse,
+	.build		= nftnl_expr_tproxy_build,
+	.snprintf	= nftnl_expr_tproxy_snprintf,
+};
diff --git a/src/expr_ops.c b/src/expr_ops.c
index cbb2a1b..72a4679 100644
--- a/src/expr_ops.c
+++ b/src/expr_ops.c
@@ -22,6 +22,7 @@ extern struct expr_ops expr_ops_match;
 extern struct expr_ops expr_ops_meta;
 extern struct expr_ops expr_ops_ng;
 extern struct expr_ops expr_ops_nat;
+extern struct expr_ops expr_ops_tproxy;
 extern struct expr_ops expr_ops_objref;
 extern struct expr_ops expr_ops_payload;
 extern struct expr_ops expr_ops_range;
@@ -60,6 +61,7 @@ static struct expr_ops *expr_ops[] = {
 	&expr_ops_meta,
 	&expr_ops_ng,
 	&expr_ops_nat,
+	&expr_ops_tproxy,
 	&expr_ops_notrack,
 	&expr_ops_payload,
 	&expr_ops_range,