src: add ct expectation support

Add support for ct expectation objects, used to define specific
expectations.

Signed-off-by: Stéphane Veyret <sveyret@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

6 files changed, 244 insertions, 1 deletions

diff --git a/include/libnftnl/object.h b/include/libnftnl/object.h
index 4ce2230..cce0713 100644
--- a/include/libnftnl/object.h
+++ b/include/libnftnl/object.h
@@ -71,6 +71,14 @@ enum {
 };
 
 enum {
+	NFTNL_OBJ_CT_EXPECT_L3PROTO	= NFTNL_OBJ_BASE,
+	NFTNL_OBJ_CT_EXPECT_L4PROTO,
+	NFTNL_OBJ_CT_EXPECT_DPORT,
+	NFTNL_OBJ_CT_EXPECT_TIMEOUT,
+	NFTNL_OBJ_CT_EXPECT_SIZE,
+};
+
+enum {
 	NFTNL_OBJ_LIMIT_RATE	= NFTNL_OBJ_BASE,
 	NFTNL_OBJ_LIMIT_UNIT,
 	NFTNL_OBJ_LIMIT_BURST,
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index fd38cdc..7eb8a5b 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -1429,6 +1429,17 @@ enum nft_ct_timeout_attributes {
 };
 #define NFTA_CT_TIMEOUT_MAX	(__NFTA_CT_TIMEOUT_MAX - 1)
 
+enum nft_ct_expectation_attributes {
+	NFTA_CT_EXPECT_UNSPEC,
+	NFTA_CT_EXPECT_L3PROTO,
+	NFTA_CT_EXPECT_L4PROTO,
+	NFTA_CT_EXPECT_DPORT,
+	NFTA_CT_EXPECT_TIMEOUT,
+	NFTA_CT_EXPECT_SIZE,
+	__NFTA_CT_EXPECT_MAX,
+};
+#define NFTA_CT_EXPECT_MAX	(__NFTA_CT_EXPECT_MAX - 1)
+
 #define NFT_OBJECT_UNSPEC	0
 #define NFT_OBJECT_COUNTER	1
 #define NFT_OBJECT_QUOTA	2
@@ -1438,7 +1449,8 @@ enum nft_ct_timeout_attributes {
 #define NFT_OBJECT_TUNNEL	6
 #define NFT_OBJECT_CT_TIMEOUT	7
 #define NFT_OBJECT_SECMARK	8
-#define __NFT_OBJECT_MAX	9
+#define NFT_OBJECT_CT_EXPECT	9
+#define __NFT_OBJECT_MAX	10
 #define NFT_OBJECT_MAX		(__NFT_OBJECT_MAX - 1)
 
 /**
diff --git a/include/obj.h b/include/obj.h
index 35b5c40..9394d79 100644
--- a/include/obj.h
+++ b/include/obj.h
@@ -42,6 +42,13 @@ struct nftnl_obj {
 			uint8_t 	l4proto;
 			uint32_t	timeout[NFTNL_CTTIMEOUT_ARRAY_MAX];
 		} ct_timeout;
+		struct nftnl_obj_ct_expect {
+			uint16_t	l3proto;
+			uint16_t	dport;
+			uint8_t		l4proto;
+			uint8_t		size;
+			uint32_t	timeout;
+		} ct_expect;
 		struct nftnl_obj_limit {
 			uint64_t	rate;
 			uint64_t	unit;
@@ -99,6 +106,7 @@ extern struct obj_ops obj_ops_counter;
 extern struct obj_ops obj_ops_quota;
 extern struct obj_ops obj_ops_ct_helper;
 extern struct obj_ops obj_ops_ct_timeout;
+extern struct obj_ops obj_ops_ct_expect;
 extern struct obj_ops obj_ops_limit;
 extern struct obj_ops obj_ops_tunnel;
 extern struct obj_ops obj_ops_secmark;
diff --git a/src/Makefile.am b/src/Makefile.am
index 2d5873f..8f9c022 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -65,4 +65,5 @@ libnftnl_la_SOURCES = utils.c		\
 		      obj/limit.c	\
 		      obj/ct_timeout.c 	\
 		      obj/secmark.c	\
+		      obj/ct_expect.c 	\
 		      libnftnl.map
diff --git a/src/obj/ct_expect.c b/src/obj/ct_expect.c
new file mode 100644
index 0000000..c0bb5ba
--- /dev/null
+++ b/src/obj/ct_expect.c
@@ -0,0 +1,213 @@
+/*
+ * (C) 2019 by Stéphane Veyret <sveyret@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 <arpa/inet.h>
+#include <errno.h>
+
+#include <libmnl/libmnl.h>
+
+#include "obj.h"
+
+static int nftnl_obj_ct_expect_set(struct nftnl_obj *e, uint16_t type,
+				   const void *data, uint32_t data_len)
+{
+	struct nftnl_obj_ct_expect *exp = nftnl_obj_data(e);
+
+	switch (type) {
+	case NFTNL_OBJ_CT_EXPECT_L3PROTO:
+		memcpy(&exp->l3proto, data, sizeof(exp->l3proto));
+		break;
+	case NFTNL_OBJ_CT_EXPECT_L4PROTO:
+		memcpy(&exp->l4proto, data, sizeof(exp->l4proto));
+		break;
+	case NFTNL_OBJ_CT_EXPECT_DPORT:
+		memcpy(&exp->dport, data, sizeof(exp->dport));
+		break;
+	case NFTNL_OBJ_CT_EXPECT_TIMEOUT:
+		memcpy(&exp->timeout, data, sizeof(exp->timeout));
+		break;
+	case NFTNL_OBJ_CT_EXPECT_SIZE:
+		memcpy(&exp->size, data, sizeof(exp->size));
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static const void *nftnl_obj_ct_expect_get(const struct nftnl_obj *e,
+					   uint16_t type, uint32_t *data_len)
+{
+	struct nftnl_obj_ct_expect *exp = nftnl_obj_data(e);
+
+	switch (type) {
+	case NFTNL_OBJ_CT_EXPECT_L3PROTO:
+		*data_len = sizeof(exp->l3proto);
+		return &exp->l3proto;
+	case NFTNL_OBJ_CT_EXPECT_L4PROTO:
+		*data_len = sizeof(exp->l4proto);
+		return &exp->l4proto;
+	case NFTNL_OBJ_CT_EXPECT_DPORT:
+		*data_len = sizeof(exp->dport);
+		return &exp->dport;
+	case NFTNL_OBJ_CT_EXPECT_TIMEOUT:
+		*data_len = sizeof(exp->timeout);
+		return &exp->timeout;
+	case NFTNL_OBJ_CT_EXPECT_SIZE:
+		*data_len = sizeof(exp->size);
+		return &exp->size;
+	}
+	return NULL;
+}
+
+static int nftnl_obj_ct_expect_cb(const struct nlattr *attr, void *data)
+{
+	int type = mnl_attr_get_type(attr);
+	const struct nlattr **tb = data;
+
+	if (mnl_attr_type_valid(attr, NFTA_CT_EXPECT_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch (type) {
+	case NFTA_CT_EXPECT_L3PROTO:
+		if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
+			abi_breakage();
+		break;
+	case NFTA_CT_EXPECT_L4PROTO:
+		if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0)
+			abi_breakage();
+		break;
+	case NFTA_CT_EXPECT_DPORT:
+		if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
+			abi_breakage();
+		break;
+	case NFTA_CT_EXPECT_TIMEOUT:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+			abi_breakage();
+		break;
+	case NFTA_CT_EXPECT_SIZE:
+		if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0)
+			abi_breakage();
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void
+nftnl_obj_ct_expect_build(struct nlmsghdr *nlh, const struct nftnl_obj *e)
+{
+	struct nftnl_obj_ct_expect *exp = nftnl_obj_data(e);
+
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_L3PROTO))
+		mnl_attr_put_u16(nlh, NFTA_CT_EXPECT_L3PROTO, htons(exp->l3proto));
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_L4PROTO))
+		mnl_attr_put_u8(nlh, NFTA_CT_EXPECT_L4PROTO, exp->l4proto);
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_DPORT))
+		mnl_attr_put_u16(nlh, NFTA_CT_EXPECT_DPORT, htons(exp->dport));
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_TIMEOUT))
+		mnl_attr_put_u32(nlh, NFTA_CT_EXPECT_TIMEOUT, exp->timeout);
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_SIZE))
+		mnl_attr_put_u8(nlh, NFTA_CT_EXPECT_SIZE, exp->size);
+}
+
+static int
+nftnl_obj_ct_expect_parse(struct nftnl_obj *e, struct nlattr *attr)
+{
+	struct nftnl_obj_ct_expect *exp = nftnl_obj_data(e);
+	struct nlattr *tb[NFTA_CT_EXPECT_MAX + 1] = {};
+
+	if (mnl_attr_parse_nested(attr, nftnl_obj_ct_expect_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_CT_EXPECT_L3PROTO]) {
+		exp->l3proto = ntohs(mnl_attr_get_u16(tb[NFTA_CT_EXPECT_L3PROTO]));
+		e->flags |= (1 << NFTNL_OBJ_CT_EXPECT_L3PROTO);
+	}
+	if (tb[NFTA_CT_EXPECT_L4PROTO]) {
+		exp->l4proto = mnl_attr_get_u8(tb[NFTA_CT_EXPECT_L4PROTO]);
+		e->flags |= (1 << NFTNL_OBJ_CT_EXPECT_L4PROTO);
+	}
+	if (tb[NFTA_CT_EXPECT_DPORT]) {
+		exp->dport = ntohs(mnl_attr_get_u16(tb[NFTA_CT_EXPECT_DPORT]));
+		e->flags |= (1 << NFTNL_OBJ_CT_EXPECT_DPORT);
+	}
+	if (tb[NFTA_CT_EXPECT_TIMEOUT]) {
+		exp->timeout = mnl_attr_get_u32(tb[NFTA_CT_EXPECT_TIMEOUT]);
+		e->flags |= (1 << NFTNL_OBJ_CT_EXPECT_TIMEOUT);
+	}
+	if (tb[NFTA_CT_EXPECT_SIZE]) {
+		exp->size = mnl_attr_get_u8(tb[NFTA_CT_EXPECT_SIZE]);
+		e->flags |= (1 << NFTNL_OBJ_CT_EXPECT_SIZE);
+	}
+
+	return 0;
+}
+
+static int nftnl_obj_ct_expect_snprintf_default(char *buf, size_t len,
+						const struct nftnl_obj *e)
+{
+	int ret = 0;
+	int offset = 0, remain = len;
+	struct nftnl_obj_ct_expect *exp = nftnl_obj_data(e);
+
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_L3PROTO)) {
+		ret = snprintf(buf + offset, len, "family %d ", exp->l3proto);
+		SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+	}
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_L4PROTO)) {
+		ret = snprintf(buf + offset, len, "protocol %d ", exp->l4proto);
+		SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+	}
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_DPORT)) {
+		ret = snprintf(buf + offset, len, "dport %d ", exp->dport);
+		SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+	}
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_TIMEOUT)) {
+		ret = snprintf(buf + offset, len, "timeout %d ", exp->timeout);
+		SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+	}
+	if (e->flags & (1 << NFTNL_OBJ_CT_EXPECT_SIZE)) {
+		ret = snprintf(buf + offset, len, "size %d ", exp->size);
+		SNPRINTF_BUFFER_SIZE(ret, remain, offset);
+	}
+
+	buf[offset] = '\0';
+	return offset;
+}
+
+static int nftnl_obj_ct_expect_snprintf(char *buf, size_t len, uint32_t type,
+					uint32_t flags,
+					const struct nftnl_obj *e)
+{
+	if (len)
+		buf[0] = '\0';
+
+	switch (type) {
+	case NFTNL_OUTPUT_DEFAULT:
+		return nftnl_obj_ct_expect_snprintf_default(buf, len, e);
+	case NFTNL_OUTPUT_JSON:
+	default:
+		break;
+	}
+	return -1;
+}
+
+struct obj_ops obj_ops_ct_expect = {
+	.name		= "ct_expect",
+	.type		= NFT_OBJECT_CT_EXPECT,
+	.alloc_len	= sizeof(struct nftnl_obj_ct_expect),
+	.max_attr	= NFTA_CT_EXPECT_MAX,
+	.set		= nftnl_obj_ct_expect_set,
+	.get		= nftnl_obj_ct_expect_get,
+	.parse		= nftnl_obj_ct_expect_parse,
+	.build		= nftnl_obj_ct_expect_build,
+	.snprintf	= nftnl_obj_ct_expect_snprintf,
+};
diff --git a/src/object.c b/src/object.c
index 5c8d183..d8c87ee 100644
--- a/src/object.c
+++ b/src/object.c
@@ -33,6 +33,7 @@ static struct obj_ops *obj_ops[__NFT_OBJECT_MAX] = {
 	[NFT_OBJECT_TUNNEL]	= &obj_ops_tunnel,
 	[NFT_OBJECT_CT_TIMEOUT] = &obj_ops_ct_timeout,
 	[NFT_OBJECT_SECMARK]	= &obj_ops_secmark,
+	[NFT_OBJECT_CT_EXPECT]	= &obj_ops_ct_expect,
 };
 
 static struct obj_ops *nftnl_obj_ops_lookup(uint32_t type)