tcpopt: allow to check for presence of any tcp option

nft currently doesn't allow to check for presence of arbitrary tcp options.
Only known options where nft provides a template can be tested for.

This allows to test for presence of raw protocol values as well.

Example:

tcp option 42 exists

Signed-off-by: Florian Westphal <fw@strlen.de>

8 files changed, 65 insertions, 57 deletions

diff --git a/include/expression.h b/include/expression.h
index b039882c..894a68d2 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -311,7 +311,8 @@ struct expr {
 			/* EXPR_EXTHDR */
 			const struct exthdr_desc	*desc;
 			const struct proto_hdr_template	*tmpl;
-			unsigned int			offset;
+			uint16_t			offset;
+			uint8_t				raw_type;
 			enum nft_exthdr_op		op;
 			unsigned int			flags;
 		} exthdr;
diff --git a/src/exthdr.c b/src/exthdr.c
index e1b7f14d..8995ad17 100644
--- a/src/exthdr.c
+++ b/src/exthdr.c
@@ -52,6 +52,13 @@ static void exthdr_expr_print(const struct expr *expr, struct output_ctx *octx)
 		 */
 		unsigned int offset = expr->exthdr.offset / 64;
 
+		if (expr->exthdr.desc == NULL &&
+		    expr->exthdr.offset == 0 &&
+		    expr->exthdr.flags & NFT_EXTHDR_F_PRESENT) {
+			nft_print(octx, "tcp option %d", expr->exthdr.raw_type);
+			return;
+		}
+
 		nft_print(octx, "tcp option %s", expr->exthdr.desc->name);
 		if (expr->exthdr.flags & NFT_EXTHDR_F_PRESENT)
 			return;
@@ -79,6 +86,7 @@ static bool exthdr_expr_cmp(const struct expr *e1, const struct expr *e2)
 	return e1->exthdr.desc == e2->exthdr.desc &&
 	       e1->exthdr.tmpl == e2->exthdr.tmpl &&
 	       e1->exthdr.op == e2->exthdr.op &&
+	       e1->exthdr.raw_type == e2->exthdr.raw_type &&
 	       e1->exthdr.flags == e2->exthdr.flags;
 }
 
@@ -89,6 +97,7 @@ static void exthdr_expr_clone(struct expr *new, const struct expr *expr)
 	new->exthdr.offset = expr->exthdr.offset;
 	new->exthdr.op = expr->exthdr.op;
 	new->exthdr.flags = expr->exthdr.flags;
+	new->exthdr.raw_type = expr->exthdr.raw_type;
 }
 
 #define NFTNL_UDATA_EXTHDR_DESC 0
@@ -192,6 +201,7 @@ struct expr *exthdr_expr_alloc(const struct location *loc,
 	expr = expr_alloc(loc, EXPR_EXTHDR, tmpl->dtype,
 			  BYTEORDER_BIG_ENDIAN, tmpl->len);
 	expr->exthdr.desc = desc;
+	expr->exthdr.raw_type = desc ? desc->type : 0;
 	expr->exthdr.tmpl = tmpl;
 	expr->exthdr.offset = tmpl->offset;
 	return expr;
@@ -270,6 +280,8 @@ void exthdr_init_raw(struct expr *expr, uint8_t type,
 	unsigned int i;
 
 	assert(expr->etype == EXPR_EXTHDR);
+	expr->exthdr.raw_type = type;
+
 	if (op == NFT_EXTHDR_OP_TCPOPT)
 		return tcpopt_init_raw(expr, type, offset, len, flags);
 	if (op == NFT_EXTHDR_OP_IPV4)
diff --git a/src/ipopt.c b/src/ipopt.c
index 7ecb8b9c..5f9f908c 100644
--- a/src/ipopt.c
+++ b/src/ipopt.c
@@ -103,6 +103,7 @@ struct expr *ipopt_expr_alloc(const struct location *loc, uint8_t type,
 	expr->exthdr.tmpl   = tmpl;
 	expr->exthdr.op     = NFT_EXTHDR_OP_IPV4;
 	expr->exthdr.offset = tmpl->offset + calc_offset(desc, tmpl, ptr);
+	expr->exthdr.raw_type = desc->type;
 
 	return expr;
 }
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index a37e4b94..05af8bb1 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -206,7 +206,7 @@ static void netlink_gen_exthdr(struct netlink_linearize_ctx *ctx,
 	nle = alloc_nft_expr("exthdr");
 	netlink_put_register(nle, NFTNL_EXPR_EXTHDR_DREG, dreg);
 	nftnl_expr_set_u8(nle, NFTNL_EXPR_EXTHDR_TYPE,
-			  expr->exthdr.desc->type);
+			  expr->exthdr.raw_type);
 	nftnl_expr_set_u32(nle, NFTNL_EXPR_EXTHDR_OFFSET, offset / BITS_PER_BYTE);
 	nftnl_expr_set_u32(nle, NFTNL_EXPR_EXTHDR_LEN,
 			   div_round_up(expr->len, BITS_PER_BYTE));
diff --git a/src/parser_bison.y b/src/parser_bison.y
index 7dedbd25..9a2b1b6f 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -5224,6 +5224,13 @@ tcp_hdr_option_type	:	EOL		{ $$ = TCPOPT_KIND_EOL; }
 			|	SACK3		{ $$ = TCPOPT_KIND_SACK3; }
 			|	ECHO		{ $$ = TCPOPT_KIND_ECHO; }
 			|	TIMESTAMP	{ $$ = TCPOPT_KIND_TIMESTAMP; }
+			|	NUM		{
+				if ($1 > 255) {
+					erec_queue(error(&@1, "value too large"), state->msgs);
+					YYERROR;
+				}
+				$$ = $1;
+			}
 			;
 
 tcp_hdr_option_field	:	KIND		{ $$ = TCPOPT_COMMON_KIND; }
diff --git a/src/tcpopt.c b/src/tcpopt.c
index d1dd13b8..1cf97a56 100644
--- a/src/tcpopt.c
+++ b/src/tcpopt.c
@@ -103,6 +103,19 @@ const struct exthdr_desc *tcpopt_protocols[] = {
 	[TCPOPT_KIND_TIMESTAMP]		= &tcpopt_timestamp,
 };
 
+/**
+ * tcpopt_expr_alloc - allocate tcp option extension expression
+ *
+ * @loc: location from parser
+ * @kind: raw tcp option value to find in packet
+ * @field: highlevel field to find in the option if @kind is present in packet
+ *
+ * Allocate a new tcp option expression.
+ * @kind is the raw option value to find in the packet.
+ * Exception: SACK may use extra OOB data that is mangled here.
+ *
+ * @field is the optional field to extract from the @type option.
+ */
 struct expr *tcpopt_expr_alloc(const struct location *loc,
 			       unsigned int kind,
 			       unsigned int field)
@@ -138,8 +151,22 @@ struct expr *tcpopt_expr_alloc(const struct location *loc,
 	if (kind < array_size(tcpopt_protocols))
 		desc = tcpopt_protocols[kind];
 
-	if (!desc)
-		return NULL;
+	if (!desc) {
+		if (field != TCPOPT_COMMON_KIND || kind > 255)
+			return NULL;
+
+		expr = expr_alloc(loc, EXPR_EXTHDR, &integer_type,
+				  BYTEORDER_BIG_ENDIAN, 8);
+
+		desc = tcpopt_protocols[TCPOPT_NOP];
+		tmpl = &desc->templates[field];
+		expr->exthdr.desc   = desc;
+		expr->exthdr.tmpl   = tmpl;
+		expr->exthdr.op = NFT_EXTHDR_OP_TCPOPT;
+		expr->exthdr.raw_type = kind;
+		return expr;
+	}
+
 	tmpl = &desc->templates[field];
 	if (!tmpl)
 		return NULL;
@@ -149,6 +176,7 @@ struct expr *tcpopt_expr_alloc(const struct location *loc,
 	expr->exthdr.desc   = desc;
 	expr->exthdr.tmpl   = tmpl;
 	expr->exthdr.op     = NFT_EXTHDR_OP_TCPOPT;
+	expr->exthdr.raw_type = desc->type;
 	expr->exthdr.offset = tmpl->offset;
 
 	return expr;
@@ -165,6 +193,10 @@ void tcpopt_init_raw(struct expr *expr, uint8_t type, unsigned int off,
 	expr->len = len;
 	expr->exthdr.flags = flags;
 	expr->exthdr.offset = off;
+	expr->exthdr.op = NFT_EXTHDR_OP_TCPOPT;
+
+	if (flags & NFT_EXTHDR_F_PRESENT)
+		datatype_set(expr, &boolean_type);
 
 	if (type >= array_size(tcpopt_protocols))
 		return;
@@ -178,12 +210,10 @@ void tcpopt_init_raw(struct expr *expr, uint8_t type, unsigned int off,
 		if (tmpl->offset != off || tmpl->len != len)
 			continue;
 
-		if (flags & NFT_EXTHDR_F_PRESENT)
-			datatype_set(expr, &boolean_type);
-		else
+		if ((flags & NFT_EXTHDR_F_PRESENT) == 0)
 			datatype_set(expr, tmpl->dtype);
+
 		expr->exthdr.tmpl = tmpl;
-		expr->exthdr.op   = NFT_EXTHDR_OP_TCPOPT;
 		break;
 	}
 }
diff --git a/tests/py/any/tcpopt.t b/tests/py/any/tcpopt.t
index 1d42de87..7b17014b 100644
--- a/tests/py/any/tcpopt.t
+++ b/tests/py/any/tcpopt.t
@@ -30,6 +30,7 @@ tcp option timestamp kind 1;ok
 tcp option timestamp length 1;ok
 tcp option timestamp tsval 1;ok
 tcp option timestamp tsecr 1;ok
+tcp option 255 missing;ok
 
 tcp option foobar;fail
 tcp option foo bar;fail
@@ -38,6 +39,7 @@ tcp option eol left 1;fail
 tcp option eol left 1;fail
 tcp option sack window;fail
 tcp option sack window 1;fail
+tcp option 256 exists;fail
 
 tcp option window exists;ok
 tcp option window missing;ok
diff --git a/tests/py/any/tcpopt.t.payload b/tests/py/any/tcpopt.t.payload
index 9c480c8b..34f8e26c 100644
--- a/tests/py/any/tcpopt.t.payload
+++ b/tests/py/any/tcpopt.t.payload
@@ -510,39 +510,18 @@ inet
   [ cmp eq reg 1 0x01000000 ]
 
 # tcp option timestamp tsecr 1
-ip 
-  [ meta load l4proto => reg 1 ]
-  [ cmp eq reg 1 0x00000006 ]
-  [ exthdr load tcpopt 4b @ 8 + 6 => reg 1 ]
-  [ cmp eq reg 1 0x01000000 ]
-
-# tcp option timestamp tsecr 1
-ip6 
-  [ meta load l4proto => reg 1 ]
-  [ cmp eq reg 1 0x00000006 ]
-  [ exthdr load tcpopt 4b @ 8 + 6 => reg 1 ]
-  [ cmp eq reg 1 0x01000000 ]
-
-# tcp option timestamp tsecr 1
 inet 
   [ meta load l4proto => reg 1 ]
   [ cmp eq reg 1 0x00000006 ]
   [ exthdr load tcpopt 4b @ 8 + 6 => reg 1 ]
   [ cmp eq reg 1 0x01000000 ]
 
-# tcp option window exists
-ip 
-  [ meta load l4proto => reg 1 ]
-  [ cmp eq reg 1 0x00000006 ]
-  [ exthdr load tcpopt 1b @ 3 + 0 present => reg 1 ]
-  [ cmp eq reg 1 0x00000001 ]
-
-# tcp option window exists
-ip6 
+# tcp option 255 missing
+inet
   [ meta load l4proto => reg 1 ]
   [ cmp eq reg 1 0x00000006 ]
-  [ exthdr load tcpopt 1b @ 3 + 0 present => reg 1 ]
-  [ cmp eq reg 1 0x00000001 ]
+  [ exthdr load tcpopt 1b @ 255 + 0 present => reg 1 ]
+  [ cmp eq reg 1 0x00000000 ]
 
 # tcp option window exists
 inet 
@@ -552,20 +531,6 @@ inet
   [ cmp eq reg 1 0x00000001 ]
 
 # tcp option window missing
-ip 
-  [ meta load l4proto => reg 1 ]
-  [ cmp eq reg 1 0x00000006 ]
-  [ exthdr load tcpopt 1b @ 3 + 0 present => reg 1 ]
-  [ cmp eq reg 1 0x00000000 ]
-
-# tcp option window missing
-ip6 
-  [ meta load l4proto => reg 1 ]
-  [ cmp eq reg 1 0x00000006 ]
-  [ exthdr load tcpopt 1b @ 3 + 0 present => reg 1 ]
-  [ cmp eq reg 1 0x00000000 ]
-
-# tcp option window missing
 inet 
   [ meta load l4proto => reg 1 ]
   [ cmp eq reg 1 0x00000006 ]
@@ -573,16 +538,6 @@ inet
   [ cmp eq reg 1 0x00000000 ]
 
 # tcp option maxseg size set 1360
-ip 
-  [ immediate reg 1 0x00005005 ]
-  [ exthdr write tcpopt reg 1 => 2b @ 2 + 2 ]
-
-# tcp option maxseg size set 1360
-ip6 
-  [ immediate reg 1 0x00005005 ]
-  [ exthdr write tcpopt reg 1 => 2b @ 2 + 2 ]
-
-# tcp option maxseg size set 1360
 inet 
   [ immediate reg 1 0x00005005 ]
   [ exthdr write tcpopt reg 1 => 2b @ 2 + 2 ]