[PATCH 1/2 nft v2] src: osf: add ttl option support

[Fernando Fernandez Mancera <ffmancera@xxxxxxxxxx>]

Add support for ttl option in "osf" expression. Example:

table ip foo {
	chain bar {
		type filter hook input priority filter; policy accept;
		osf ttl nocheck name "Linux"
	}
}

Signed-off-by: Fernando Fernandez Mancera <ffmancera@xxxxxxxxxx>
---
v1: initial patch
v2: use "ttl-global" or "ttl-nocheck" instead of "1" or "2"
---
 include/expression.h                |  4 ++++
 include/linux/netfilter/nf_tables.h |  2 ++
 include/osf.h                       |  2 +-
 src/netlink_delinearize.c           |  5 ++++-
 src/netlink_linearize.c             |  1 +
 src/osf.c                           | 26 ++++++++++++++++++++++++--
 src/parser_bison.y                  | 17 +++++++++++++++--
 7 files changed, 51 insertions(+), 6 deletions(-)

diff --git a/include/expression.h b/include/expression.h
index fb52abf..a794128 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -345,6 +345,10 @@ struct expr {
 			uint8_t		direction;
 			uint8_t		spnum;
 		} xfrm;
+		struct {
+			/* EXPR_OSF */
+			uint8_t			ttl;
+		} osf;
 	};
 };
 
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index 169c2ab..1003942 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -939,10 +939,12 @@ enum nft_socket_keys {
  * enum nft_osf_attributes - nf_tables osf expression netlink attributes
  *
  * @NFTA_OSF_DREG: destination register (NLA_U32: nft_registers)
+ * @NFTA_OSF_TTL: Value of the TTL osf option (NLA_U8)
  */
 enum nft_osf_attributes {
 	NFTA_OSF_UNSPEC,
 	NFTA_OSF_DREG,
+	NFTA_OSF_TTL,
 	__NFTA_OSF_MAX
 };
 #define NFT_OSF_MAX		(__NFTA_OSF_MAX - 1)
diff --git a/include/osf.h b/include/osf.h
index 54cdd4a..23ea34d 100644
--- a/include/osf.h
+++ b/include/osf.h
@@ -1,7 +1,7 @@
 #ifndef NFTABLES_OSF_H
 #define NFTABLES_OSF_H
 
-struct expr *osf_expr_alloc(const struct location *loc);
+struct expr *osf_expr_alloc(const struct location *loc, const uint8_t ttl);
 
 extern int nfnl_osf_load_fingerprints(struct netlink_ctx *ctx, int del);
 
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 0a6ebe0..d474893 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -655,8 +655,11 @@ static void netlink_parse_osf(struct netlink_parse_ctx *ctx,
 {
 	enum nft_registers dreg;
 	struct expr *expr;
+	uint8_t ttl;
+
+	ttl = nftnl_expr_get_u8(nle, NFTNL_EXPR_OSF_TTL);
+	expr = osf_expr_alloc(loc, ttl);
 
-	expr = osf_expr_alloc(loc);
 	dreg = netlink_parse_register(nle, NFTNL_EXPR_OSF_DREG);
 	netlink_set_register(ctx, dreg, expr);
 }
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 0ac51bd..0c8f5fe 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -227,6 +227,7 @@ static void netlink_gen_osf(struct netlink_linearize_ctx *ctx,
 
 	nle = alloc_nft_expr("osf");
 	netlink_put_register(nle, NFTNL_EXPR_OSF_DREG, dreg);
+	nftnl_expr_set_u8(nle, NFTNL_EXPR_OSF_TTL, expr->osf.ttl);
 	nftnl_rule_add_expr(ctx->nlr, nle);
 }
 
diff --git a/src/osf.c b/src/osf.c
index 85c9573..c7dd25f 100644
--- a/src/osf.c
+++ b/src/osf.c
@@ -5,13 +5,32 @@
 #include <osf.h>
 #include <json.h>
 
+static const char *osf_ttl_int_to_str(const uint8_t ttl)
+{
+	if (ttl == 1)
+		return "ttl global";
+	else if (ttl == 2)
+		return "ttl nocheck";
+
+	return "";
+}
+
 static void osf_expr_print(const struct expr *expr, struct output_ctx *octx)
 {
-	nft_print(octx, "osf name");
+	const char *ttl_str;
+
+	ttl_str = osf_ttl_int_to_str(expr->osf.ttl);
+	nft_print(octx, "osf %s name", ttl_str);
 }
 
 static void osf_expr_clone(struct expr *new, const struct expr *expr)
 {
+	new->osf.ttl = expr->osf.ttl;
+}
+
+static bool osf_expr_cmp(const struct expr *e1, const struct expr *e2)
+{
+	return e1->osf.ttl == e2->osf.ttl;
 }
 
 static const struct expr_ops osf_expr_ops = {
@@ -19,10 +38,11 @@ static const struct expr_ops osf_expr_ops = {
 	.name		= "osf",
 	.print		= osf_expr_print,
 	.clone		= osf_expr_clone,
+	.cmp		= osf_expr_cmp,
 	.json		= osf_expr_json,
 };
 
-struct expr *osf_expr_alloc(const struct location *loc)
+struct expr *osf_expr_alloc(const struct location *loc, const uint8_t ttl)
 {
 	unsigned int len = NFT_OSF_MAXGENRELEN * BITS_PER_BYTE;
 	const struct datatype *type = &string_type;
@@ -31,5 +51,7 @@ struct expr *osf_expr_alloc(const struct location *loc)
 	expr = expr_alloc(loc, &osf_expr_ops, type,
 			  BYTEORDER_HOST_ENDIAN, len);
 
+	expr->osf.ttl = ttl;
+
 	return expr;
 }
diff --git a/src/parser_bison.y b/src/parser_bison.y
index 831090b..a7ec858 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -739,6 +739,7 @@ int nft_lex(void *, void *, void *);
 %type <val>			fib_tuple	fib_result	fib_flag
 
 %type <expr>			osf_expr
+%type <val>			osf_ttl
 %destructor { expr_free($$); }	osf_expr
 
 %type <val>			markup_format
@@ -3112,9 +3113,21 @@ fib_tuple		:  	fib_flag	DOT	fib_tuple
 			|	fib_flag
 			;
 
-osf_expr		:	OSF	NAME
+osf_expr		:	OSF	osf_ttl		NAME
 			{
-				$$ = osf_expr_alloc(&@$);
+				$$ = osf_expr_alloc(&@$, $2);
+			}
+			;
+
+osf_ttl			:	/* empty */	{ $$ = 0; }
+			|	STRING
+			{
+				if (!strcmp($1, "ttl-global"))
+					$$ = 1;
+				else if (!strcmp($1, "ttl-nocheck"))
+					$$ = 2;
+				else
+					$$ = 3;
 			}
 			;
 
-- 
2.19.0