[PATCH libnftnl] src: synproxy stateful object support

[PATCH libnftnl] src: synproxy stateful object support

[Fernando Fernandez Mancera]

This patch adds synproxy stateful object support.

Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
---
 include/libnftnl/object.h           |   6 ++
 include/linux/netfilter/nf_tables.h |   3 +-
 include/obj.h                       |   6 ++
 src/Makefile.am                     |   1 +
 src/obj/synproxy.c                  | 161 ++++++++++++++++++++++++++++
 src/object.c                        |   1 +
 6 files changed, 177 insertions(+), 1 deletion(-)
 create mode 100644 src/obj/synproxy.c

diff --git a/include/libnftnl/object.h b/include/libnftnl/object.h
index cce0713..c5ea88e 100644
--- a/include/libnftnl/object.h
+++ b/include/libnftnl/object.h
@@ -86,6 +86,12 @@ enum {
 	NFTNL_OBJ_LIMIT_FLAGS,
 };
 
+enum {
+	NFTNL_OBJ_SYNPROXY_MSS	= NFTNL_OBJ_BASE,
+	NFTNL_OBJ_SYNPROXY_WSCALE,
+	NFTNL_OBJ_SYNPROXY_FLAGS,
+};
+
 enum {
 	NFTNL_OBJ_TUNNEL_ID	= NFTNL_OBJ_BASE,
 	NFTNL_OBJ_TUNNEL_IPV4_SRC,
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index 75e083e..2e49bc6 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -1481,7 +1481,8 @@ enum nft_ct_expectation_attributes {
 #define NFT_OBJECT_CT_TIMEOUT	7
 #define NFT_OBJECT_SECMARK	8
 #define NFT_OBJECT_CT_EXPECT	9
-#define __NFT_OBJECT_MAX	10
+#define NFT_OBJECT_SYNPROXY	10
+#define __NFT_OBJECT_MAX	11
 #define NFT_OBJECT_MAX		(__NFT_OBJECT_MAX - 1)
 
 /**
diff --git a/include/obj.h b/include/obj.h
index 9394d79..10f806c 100644
--- a/include/obj.h
+++ b/include/obj.h
@@ -56,6 +56,11 @@ struct nftnl_obj {
 			uint32_t	type;
 			uint32_t	flags;
 		} limit;
+		struct nftnl_obj_synproxy {
+			uint16_t	mss;
+			uint8_t		wscale;
+			uint32_t	flags;
+		} synproxy;
 		struct nftnl_obj_tunnel {
 			uint32_t	id;
 			uint32_t	src_v4;
@@ -108,6 +113,7 @@ 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_synproxy;
 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 f16422c..90b1967 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -64,6 +64,7 @@ libnftnl_la_SOURCES = utils.c		\
 		      obj/quota.c	\
 		      obj/tunnel.c	\
 		      obj/limit.c	\
+		      obj/synproxy.c	\
 		      obj/ct_timeout.c 	\
 		      obj/secmark.c	\
 		      obj/ct_expect.c 	\
diff --git a/src/obj/synproxy.c b/src/obj/synproxy.c
new file mode 100644
index 0000000..56ebc85
--- /dev/null
+++ b/src/obj/synproxy.c
@@ -0,0 +1,161 @@
+#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/object.h>
+
+#include "obj.h"
+
+static int nftnl_obj_synproxy_set(struct nftnl_obj *e, uint16_t type,
+				  const void *data, uint32_t data_len)
+{
+	struct nftnl_obj_synproxy *synproxy = nftnl_obj_data(e);
+
+	switch (type) {
+	case NFTNL_OBJ_SYNPROXY_MSS:
+		synproxy->mss = *((uint16_t *)data);
+		break;
+	case NFTNL_OBJ_SYNPROXY_WSCALE:
+		synproxy->wscale = *((uint8_t *)data);
+		break;
+	case NFTNL_OBJ_SYNPROXY_FLAGS:
+		synproxy->flags = *((uint32_t *)data);
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static const void *nftnl_obj_synproxy_get(const struct nftnl_obj *e,
+					  uint16_t type, uint32_t *data_len)
+{
+	struct nftnl_obj_synproxy *synproxy = nftnl_obj_data(e);
+
+	switch (type) {
+	case NFTNL_OBJ_SYNPROXY_MSS:
+		*data_len = sizeof(synproxy->mss);
+		return &synproxy->mss;
+	case NFTNL_OBJ_SYNPROXY_WSCALE:
+		*data_len = sizeof(synproxy->wscale);
+		return &synproxy->wscale;
+	case NFTNL_OBJ_SYNPROXY_FLAGS:
+		*data_len = sizeof(synproxy->flags);
+		return &synproxy->flags;
+	}
+	return NULL;
+}
+
+static int nftnl_obj_synproxy_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_SYNPROXY_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch (type) {
+	case NFTA_SYNPROXY_MSS:
+		if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
+			abi_breakage();
+		break;
+	case NFTA_SYNPROXY_WSCALE:
+		if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0)
+			abi_breakage();
+		break;
+	case NFTA_SYNPROXY_FLAGS:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+			abi_breakage();
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void nftnl_obj_synproxy_build(struct nlmsghdr *nlh,
+				     const struct nftnl_obj *e)
+{
+	struct nftnl_obj_synproxy *synproxy = nftnl_obj_data(e);
+
+	if (e->flags & (1 << NFTNL_OBJ_SYNPROXY_MSS))
+		mnl_attr_put_u16(nlh, NFTA_SYNPROXY_MSS, htons(synproxy->mss));
+	if (e->flags & (1 << NFTNL_OBJ_SYNPROXY_WSCALE))
+		mnl_attr_put_u8(nlh, NFTA_SYNPROXY_WSCALE, synproxy->wscale);
+	if (e->flags & (1 << NFTNL_OBJ_SYNPROXY_FLAGS))
+		mnl_attr_put_u32(nlh, NFTA_SYNPROXY_FLAGS,
+				 htonl(synproxy->flags));
+}
+
+static int nftnl_obj_synproxy_parse(struct nftnl_obj *e, struct nlattr *attr)
+{
+	struct nftnl_obj_synproxy *synproxy = nftnl_obj_data(e);
+	struct nlattr *tb[NFTA_SYNPROXY_MAX + 1] = {};
+
+	if (mnl_attr_parse_nested(attr, nftnl_obj_synproxy_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_SYNPROXY_MSS]) {
+		synproxy->mss = ntohs(mnl_attr_get_u16(tb[NFTA_SYNPROXY_MSS]));
+		e->flags |= (1 << NFTNL_OBJ_SYNPROXY_MSS);
+	}
+	if (tb[NFTA_SYNPROXY_WSCALE]) {
+		synproxy->wscale = mnl_attr_get_u8(tb[NFTA_SYNPROXY_WSCALE]);
+		e->flags |= (1 << NFTNL_OBJ_SYNPROXY_WSCALE);
+	}
+	if (tb[NFTA_SYNPROXY_FLAGS]) {
+		synproxy->flags = ntohl(mnl_attr_get_u32(tb[NFTA_SYNPROXY_FLAGS]));
+		e->flags |= (1 << NFTNL_OBJ_SYNPROXY_FLAGS);
+	}
+
+	return 0;
+}
+
+static int nftnl_obj_synproxy_snprintf_default(char *buf, size_t size,
+					       const struct nftnl_obj *e)
+{
+	struct nftnl_obj_synproxy *synproxy = nftnl_obj_data(e);
+        int ret, offset = 0, len = size;
+
+        if (e->flags & (1 << NFTNL_OBJ_SYNPROXY_MSS) &&
+            e->flags & (1 << NFTNL_OBJ_SYNPROXY_WSCALE)) {
+                ret = snprintf(buf, len, "mss %u wscale %u ", synproxy->mss,
+                               synproxy->wscale);
+                SNPRINTF_BUFFER_SIZE(ret, len, offset);
+        }
+
+        return offset;
+}
+
+static int nftnl_obj_synproxy_snprintf(char *buf, size_t len, uint32_t type,
+				    uint32_t flags,
+				    const struct nftnl_obj *e)
+{
+	switch (type) {
+	case NFTNL_OUTPUT_DEFAULT:
+		return nftnl_obj_synproxy_snprintf_default(buf, len, e);
+	case NFTNL_OUTPUT_XML:
+	case NFTNL_OUTPUT_JSON:
+	default:
+		break;
+	}
+	return -1;
+}
+
+struct obj_ops obj_ops_synproxy = {
+	.name		= "synproxy",
+	.type		= NFT_OBJECT_SYNPROXY,
+	.alloc_len	= sizeof(struct nftnl_obj_synproxy),
+	.max_attr	= NFTA_SYNPROXY_MAX,
+	.set		= nftnl_obj_synproxy_set,
+	.get		= nftnl_obj_synproxy_get,
+	.parse		= nftnl_obj_synproxy_parse,
+	.build		= nftnl_obj_synproxy_build,
+	.snprintf	= nftnl_obj_synproxy_snprintf,
+};
diff --git a/src/object.c b/src/object.c
index d8c87ee..ed8e36d 100644
--- a/src/object.c
+++ b/src/object.c
@@ -34,6 +34,7 @@ static struct obj_ops *obj_ops[__NFT_OBJECT_MAX] = {
 	[NFT_OBJECT_CT_TIMEOUT] = &obj_ops_ct_timeout,
 	[NFT_OBJECT_SECMARK]	= &obj_ops_secmark,
 	[NFT_OBJECT_CT_EXPECT]	= &obj_ops_ct_expect,
+	[NFT_OBJECT_SYNPROXY]	= &obj_ops_synproxy,
 };
 
 static struct obj_ops *nftnl_obj_ops_lookup(uint32_t type)
-- 
2.20.1

Re: [PATCH libnftnl] src: synproxy stateful object support

[Pablo Neira Ayuso]

On Sat, Sep 07, 2019 at 06:05:01PM +0200, Fernando Fernandez Mancera wrote:
> This patch adds synproxy stateful object support.

Applied.