osf: add ttl option support

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

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

Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

6 files changed, 54 insertions, 8 deletions

diff --git a/src/json.c b/src/json.c
index 1cde2706..cea9f19c 100644
--- a/src/json.c
+++ b/src/json.c
@@ -857,7 +857,7 @@ json_t *socket_expr_json(const struct expr *expr, struct output_ctx *octx)
 
 json_t *osf_expr_json(const struct expr *expr, struct output_ctx *octx)
 {
-	return json_pack("{s:{s:s}}", "osf", "key", "name");
+	return json_pack("{s:{s:i, s:s}}", "osf", "ttl", expr->osf.ttl, "key", "name");
 }
 
 json_t *xfrm_expr_json(const struct expr *expr, struct output_ctx *octx)
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 3931127f..db1bf03e 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 0ac51bd0..0c8f5fe4 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 85c95739..b98d1650 100644
--- a/src/osf.c
+++ b/src/osf.c
@@ -5,13 +5,31 @@
 #include <osf.h>
 #include <json.h>
 
+static const char *osf_ttl_int_to_str(const uint8_t ttl)
+{
+	if (ttl == 1)
+		return "ttl loose ";
+	else if (ttl == 2)
+		return "ttl skip ";
+
+	return "";
+}
+
 static void osf_expr_print(const struct expr *expr, struct output_ctx *octx)
 {
-	nft_print(octx, "osf name");
+	const char *ttl_str = osf_ttl_int_to_str(expr->osf.ttl);
+
+	nft_print(octx, "osf %sname", 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 +37,11 @@ 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;
@@ -30,6 +49,7 @@ 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 36a98719..dfe30683 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -15,12 +15,14 @@
 #include <inttypes.h>
 #include <syslog.h>
 #include <netinet/ip.h>
+#include <netinet/tcp.h>
 #include <netinet/if_ether.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <linux/netfilter/nf_conntrack_tuple_common.h>
 #include <linux/netfilter/nf_nat.h>
 #include <linux/netfilter/nf_log.h>
+#include <linux/netfilter/nfnetlink_osf.h>
 #include <linux/xfrm.h>
 #include <netinet/ip_icmp.h>
 #include <netinet/icmp6.h>
@@ -740,6 +742,7 @@ 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
@@ -3173,9 +3176,27 @@ 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 */
+			{
+				$$ = NF_OSF_TTL_TRUE;
+			}
+			|	TTL	STRING
+			{
+				if (!strcmp($2, "loose"))
+					$$ = NF_OSF_TTL_LESS;
+				else if (!strcmp($2, "skip"))
+					$$ = NF_OSF_TTL_NOCHECK;
+				else {
+					erec_queue(error(&@2, "invalid ttl option"),
+						   state->msgs);
+					YYERROR;
+				}
 			}
 			;
 
diff --git a/src/parser_json.c b/src/parser_json.c
index 7047c00d..fc0dc9a9 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -376,12 +376,13 @@ static struct expr *json_parse_osf_expr(struct json_ctx *ctx,
 					const char *type, json_t *root)
 {
 	const char *key;
+	uint8_t ttl;
 
-	if (json_unpack_err(ctx, root, "{s:s}", "key", &key))
+	if (json_unpack_err(ctx, root, "{s:i, s:s}", "ttl", ttl,"key", &key))
 		return NULL;
 
 	if (!strcmp(key, "name"))
-		return osf_expr_alloc(int_loc);
+		return osf_expr_alloc(int_loc, ttl);
 
 	json_error(ctx, "Invalid osf key value.");
 	return NULL;