trafgen: parser: Allow to set function at field offset

Extend proto field expression to:

    proto_field[{index}:{len}] = {func}

which allows to specify function on the field offset via index
and value length (default is 1 - 1 byte). This rule is optional.

It was needed to keep of proto_field's copies in packet_dyn->fields
instead of original fields which allows to scpecify different functions
on the different parts of same field, also the copy of original
proto_field allows to set custom length/pkt_offset which makes such
field behave as virtual sub-field of the original one with different
length/pkt_offset but point to the same piece of header.

Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

3 files changed, 136 insertions, 67 deletions

diff --git a/trafgen_parser.y b/trafgen_parser.y
index a1b8b0c..cc1a110 100644
--- a/trafgen_parser.y
+++ b/trafgen_parser.y
@@ -74,13 +74,14 @@ extern size_t dlen;
 static int our_cpu, min_cpu = -1, max_cpu = -1;
 
 enum field_expr_type_t {
-	FIELD_EXPR_UNKNOWN,
-	FIELD_EXPR_NUMB,
-	FIELD_EXPR_MAC,
-	FIELD_EXPR_IP4_ADDR,
-	FIELD_EXPR_IP6_ADDR,
-	FIELD_EXPR_INC,
-	FIELD_EXPR_RND,
+	FIELD_EXPR_UNKNOWN	= 0,
+	FIELD_EXPR_NUMB		= 1 << 0,
+	FIELD_EXPR_MAC		= 1 << 1,
+	FIELD_EXPR_IP4_ADDR	= 1 << 2,
+	FIELD_EXPR_IP6_ADDR	= 1 << 3,
+	FIELD_EXPR_INC		= 1 << 4,
+	FIELD_EXPR_RND		= 1 << 5,
+	FIELD_EXPR_OFFSET	= 1 << 6,
 };
 
 struct proto_field_expr {
@@ -387,28 +388,44 @@ static void proto_add(enum proto_id pid)
 
 static void proto_field_set(uint32_t fid)
 {
+	memset(&field_expr, 0, sizeof(field_expr));
 	field_expr.field = proto_hdr_field_by_id(hdr, fid);
 }
 
 static void proto_field_func_setup(struct proto_field *field, struct proto_field_func *func)
 {
+	struct proto_field *field_copy;
 	struct packet_dyn *pkt_dyn;
 
-	proto_hdr_field_func_add(field->hdr, field->id, func);
+	field_copy = xmalloc(sizeof(*field));
+	memcpy(field_copy, field, sizeof(*field));
+
+	field_copy->pkt_offset += func->offset;
+	if (func->len)
+		field_copy->len = func->len;
+
+	proto_field_func_add(field_copy, func);
 
 	pkt_dyn = &packet_dyn[packetd_last];
 	pkt_dyn->flen++;
 	pkt_dyn->fields = xrealloc(pkt_dyn->fields, pkt_dyn->flen *
 				   sizeof(struct proto_field *));
-	pkt_dyn->fields[pkt_dyn->flen - 1] = field;
+
+	pkt_dyn->fields[pkt_dyn->flen - 1] = field_copy;
 }
 
 static void proto_field_expr_eval(void)
 {
 	struct proto_field *field = field_expr.field;
 
-	switch (field_expr.type) {
-	case FIELD_EXPR_NUMB:
+	if ((field_expr.type & FIELD_EXPR_OFFSET) &&
+			!((field_expr.type & FIELD_EXPR_INC) ||
+				(field_expr.type & FIELD_EXPR_RND))) {
+
+		panic("Field offset expression is valid only with function expression\n");
+	}
+
+	if (field_expr.type & FIELD_EXPR_NUMB) {
 		if (field->len == 1)
 			proto_hdr_field_set_u8(hdr, field->id, field_expr.val.number);
 		else if (field->len == 2)
@@ -417,39 +434,47 @@ static void proto_field_expr_eval(void)
 			proto_hdr_field_set_be32(hdr, field->id, field_expr.val.number);
 		else
 			proto_hdr_field_set_bytes(hdr, field->id, field_expr.val.bytes);
-		break;
-
-	case FIELD_EXPR_MAC:
+	} else if (field_expr.type & FIELD_EXPR_MAC) {
 		proto_hdr_field_set_bytes(hdr, field->id, field_expr.val.bytes);
-		break;
-
-	case FIELD_EXPR_IP4_ADDR:
+	} else if (field_expr.type & FIELD_EXPR_IP4_ADDR) {
 		proto_hdr_field_set_u32(hdr, field->id, field_expr.val.ip4_addr.s_addr);
-		break;
-
-	case FIELD_EXPR_IP6_ADDR:
+	} else if (field_expr.type & FIELD_EXPR_IP6_ADDR) {
 		proto_hdr_field_set_bytes(hdr, field->id,
 			(uint8_t *)&field_expr.val.ip6_addr.s6_addr);
-		break;
+	} else if ((field_expr.type & FIELD_EXPR_INC) ||
+			(field_expr.type & FIELD_EXPR_RND)) {
 
-	case FIELD_EXPR_INC:
-	case FIELD_EXPR_RND:
 		if (field_expr.val.func.min
 			&& field_expr.val.func.min >= field_expr.val.func.max)
 			panic("dinc(): min(%u) can't be >= max(%u)\n",
 				field_expr.val.func.min, field_expr.val.func.max);
 
 		proto_field_func_setup(field, &field_expr.val.func);
-		break;
+	} else if ((field_expr.type & FIELD_EXPR_OFFSET) &&
+			!((field_expr.type & FIELD_EXPR_INC) ||
+				(field_expr.type & FIELD_EXPR_RND))) {
 
-	case FIELD_EXPR_UNKNOWN:
-	default:
+		panic("Field expression is valid only for function value expression\n");
+	} else {
 		bug();
 	}
 
 	memset(&field_expr, 0, sizeof(field_expr));
 }
 
+static void field_index_validate(struct proto_field *field, uint16_t index, size_t len)
+{
+	if (field_expr.field->len <= index) {
+		yyerror("Invalid [index] parameter");
+		panic("Index (%u) is bigger than field's length (%zu)\n",
+		       index, field->len);
+	}
+	if (len != 1 && len != 2 && len != 4) {
+		yyerror("Invalid [index:len] parameter");
+		panic("Invalid index length - 1,2 or 4 is only allowed\n");
+	}
+}
+
 %}
 
 %union {
@@ -718,40 +743,53 @@ proto
 	| tcp_proto { }
 	;
 
+field_expr
+	: '[' skip_white number skip_white ']'
+		{ field_index_validate(field_expr.field, $3, 1);
+		  field_expr.type |= FIELD_EXPR_OFFSET;
+		  field_expr.val.func.offset = $3;
+		  field_expr.val.func.len = 1; }
+	| '[' skip_white number skip_white ':' skip_white number skip_white ']'
+		{ field_index_validate(field_expr.field, $3, $7);
+		  field_expr.type |= FIELD_EXPR_OFFSET;
+		  field_expr.val.func.offset = $3;
+		  field_expr.val.func.len = $7; }
+	;
+
 field_value_expr
-	: number { field_expr.type = FIELD_EXPR_NUMB;
+	: number { field_expr.type |= FIELD_EXPR_NUMB;
 		   field_expr.val.number = $1; }
-	| mac { field_expr.type = FIELD_EXPR_MAC;
+	| mac { field_expr.type |= FIELD_EXPR_MAC;
 		memcpy(field_expr.val.bytes, $1, sizeof(field_expr.val.bytes)); }
-	| ip4_addr { field_expr.type = FIELD_EXPR_IP4_ADDR;
+	| ip4_addr { field_expr.type |= FIELD_EXPR_IP4_ADDR;
 		     field_expr.val.ip4_addr = $1; }
-	| ip6_addr { field_expr.type = FIELD_EXPR_IP6_ADDR;
+	| ip6_addr { field_expr.type |= FIELD_EXPR_IP6_ADDR;
 		     field_expr.val.ip6_addr = $1; }
-	| K_DINC '(' ')' { field_expr.type = FIELD_EXPR_INC;
+	| K_DINC '(' ')' { field_expr.type |= FIELD_EXPR_INC;
 			   field_expr.val.func.type = PROTO_FIELD_FUNC_INC;
 			   field_expr.val.func.inc = 1; }
 	| K_DINC '(' number ')'
-			{ field_expr.type = FIELD_EXPR_INC;
+			{ field_expr.type |= FIELD_EXPR_INC;
 			  field_expr.val.func.type = PROTO_FIELD_FUNC_INC;
 			  field_expr.val.func.inc = $3; }
 	| K_DINC '(' number delimiter number ')'
-			{ field_expr.type = FIELD_EXPR_INC;
+			{ field_expr.type |= FIELD_EXPR_INC;
 			  field_expr.val.func.type  = PROTO_FIELD_FUNC_INC;
 			  field_expr.val.func.type |= PROTO_FIELD_FUNC_MIN;
 			  field_expr.val.func.min = $3;
 			  field_expr.val.func.max = $5;
 			  field_expr.val.func.inc = 1; }
 	| K_DINC '(' number delimiter number delimiter number ')'
-			{ field_expr.type = FIELD_EXPR_INC;
+			{ field_expr.type |= FIELD_EXPR_INC;
 			  field_expr.val.func.type  = PROTO_FIELD_FUNC_INC;
 			  field_expr.val.func.type |= PROTO_FIELD_FUNC_MIN;
 			  field_expr.val.func.min = $3;
 			  field_expr.val.func.max = $5;
 			  field_expr.val.func.inc = $7; }
-	| K_DRND '(' ')' { field_expr.type = FIELD_EXPR_RND;
+	| K_DRND '(' ')' { field_expr.type |= FIELD_EXPR_RND;
 			  field_expr.val.func.type = PROTO_FIELD_FUNC_RND; }
 	| K_DRND '(' number delimiter number ')'
-			{ field_expr.type = FIELD_EXPR_RND;
+			{ field_expr.type |= FIELD_EXPR_RND;
 			  field_expr.val.func.type = PROTO_FIELD_FUNC_RND;
 			  field_expr.val.func.min = $3;
 			  field_expr.val.func.max = $5; }
@@ -783,7 +821,9 @@ eth_field
 	| eth_type { proto_field_set(ETH_TYPE); }
 
 eth_expr
-	: eth_field skip_white '=' skip_white field_value_expr
+	: eth_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| eth_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	;
 
@@ -807,7 +847,9 @@ pause_field
 	;
 
 pause_expr
-	: pause_field skip_white '=' skip_white field_value_expr
+	: pause_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| pause_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	;
 
@@ -843,7 +885,9 @@ pfc_field
 	;
 
 pfc_expr
-	: pfc_field skip_white '=' skip_white field_value_expr
+	: pfc_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| pfc_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	;
 
@@ -875,7 +919,9 @@ vlan_field
 	;
 
 vlan_expr
-	: vlan_field skip_white '=' skip_white field_value_expr
+	: vlan_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| vlan_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	| K_1Q
 		{ proto_hdr_field_set_be16(hdr, VLAN_TPID, ETH_P_8021Q); }
@@ -910,7 +956,9 @@ mpls_field
 	;
 
 mpls_expr
-	: mpls_field skip_white '=' skip_white field_value_expr
+	: mpls_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| mpls_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 
 arp_proto
@@ -939,8 +987,13 @@ arp_field
 	;
 
 arp_expr
-	: arp_field skip_white '=' skip_white field_value_expr
+	: arp_field field_expr skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
+	| arp_field skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| K_OPER field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_set(ARP_OPER);
+		  proto_field_expr_eval(); }
 	| K_OPER skip_white '=' skip_white field_value_expr
 		{ proto_field_set(ARP_OPER);
 		  proto_field_expr_eval(); }
@@ -985,7 +1038,9 @@ ip4_field
 	;
 
 ip4_expr
-	: ip4_field skip_white '=' skip_white field_value_expr
+	: ip4_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| ip4_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	| K_DF  { proto_hdr_field_set_be16(hdr, IP4_DF, 1); }
 	| K_MF  { proto_hdr_field_set_be16(hdr, IP4_MF, 1); }
@@ -1022,7 +1077,9 @@ ip6_field
 	;
 
 ip6_expr
-	: ip6_field skip_white '=' skip_white field_value_expr
+	: ip6_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| ip6_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	;
 
@@ -1050,7 +1107,9 @@ icmp4_field
 	;
 
 icmp4_expr
-	: icmp4_field skip_white '=' skip_white field_value_expr
+	: icmp4_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| icmp4_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	| K_ECHO_REQUEST
 		{ proto_hdr_field_set_u8(hdr, ICMPV4_TYPE, ICMP_ECHO);
@@ -1079,8 +1138,13 @@ icmp6_field
 	;
 
 icmp6_expr
-	: icmp6_field skip_white '=' skip_white field_value_expr
+	: icmp6_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| icmp6_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
+	| K_TYPE field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_set(ICMPV6_TYPE);
+		  proto_field_expr_eval(); }
 	| K_TYPE skip_white '=' skip_white field_value_expr
 		{ proto_field_set(ICMPV6_TYPE);
 		  proto_field_expr_eval(); }
@@ -1115,7 +1179,9 @@ udp_field
 	;
 
 udp_expr
-	: udp_field skip_white '=' skip_white field_value_expr
+	: udp_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| udp_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	;
 
@@ -1145,7 +1211,9 @@ tcp_field
 	;
 
 tcp_expr
-	: tcp_field skip_white '=' skip_white field_value_expr
+	: tcp_field field_expr skip_white '=' skip_white field_value_expr
+		{ proto_field_expr_eval(); }
+	| tcp_field skip_white '=' skip_white field_value_expr
 		{ proto_field_expr_eval(); }
 	| K_CWR { proto_hdr_field_set_be16(hdr, TCP_CWR, 1); }
 	| K_ECE { proto_hdr_field_set_be16(hdr, TCP_ECE, 1); }
@@ -1225,6 +1293,10 @@ void cleanup_packets(void)
 	for (i = 0; i < dlen; ++i) {
 		free(packet_dyn[i].cnt);
 		free(packet_dyn[i].rnd);
+
+		for (j = 0; j < packet_dyn[j].flen; j++)
+			xfree(packet_dyn[i].fields[j]);
+
 		free(packet_dyn[i].fields);
 	}
 
diff --git a/trafgen_proto.c b/trafgen_proto.c
index e2b80d4..88e0846 100644
--- a/trafgen_proto.c
+++ b/trafgen_proto.c
@@ -532,11 +532,11 @@ static inline uint32_t field_inc(struct proto_field *field)
 static void field_inc_func(struct proto_field *field)
 {
 	if (field->len == 1) {
-		proto_hdr_field_set_u8(field->hdr, field->id, field_inc(field));
+		proto_field_set_u8(field, field_inc(field));
 	} else if (field->len == 2) {
-		proto_hdr_field_set_be16(field->hdr, field->id, field_inc(field));
+		proto_field_set_be16(field, field_inc(field));
 	} else if (field->len == 4) {
-		proto_hdr_field_set_be32(field->hdr, field->id, field_inc(field));
+		proto_field_set_be32(field, field_inc(field));
 	} else if (field->len > 4) {
 		uint8_t *bytes = __proto_field_get_bytes(field);
 
@@ -554,14 +554,11 @@ static inline uint32_t field_rand(struct proto_field *field)
 static void field_rnd_func(struct proto_field *field)
 {
 	if (field->len == 1) {
-		proto_hdr_field_set_u8(field->hdr, field->id,
-				    (uint8_t) field_rand(field));
+		proto_field_set_u8(field, (uint8_t) field_rand(field));
 	} else if (field->len == 2) {
-		proto_hdr_field_set_be16(field->hdr, field->id,
-				    (uint16_t) field_rand(field));
+		proto_field_set_be16(field, (uint16_t) field_rand(field));
 	} else if (field->len == 4) {
-		proto_hdr_field_set_be32(field->hdr, field->id,
-				    (uint32_t) field_rand(field));
+		proto_field_set_be32(field, (uint32_t) field_rand(field));
 	} else if (field->len > 4) {
 		uint8_t *bytes = __proto_field_get_bytes(field);
 		uint32_t i;
@@ -571,11 +568,9 @@ static void field_rnd_func(struct proto_field *field)
 	}
 }
 
-void proto_hdr_field_func_add(struct proto_hdr *hdr, uint32_t fid,
-			      struct proto_field_func *func)
+void proto_field_func_add(struct proto_field *field,
+			  struct proto_field_func *func)
 {
-	struct proto_field *field = proto_hdr_field_by_id(hdr, fid);
-
 	bug_on(!func);
 
 	field->func.update_field = func->update_field;
@@ -588,11 +583,11 @@ void proto_hdr_field_func_add(struct proto_hdr *hdr, uint32_t fid,
 		if (func->type & PROTO_FIELD_FUNC_MIN)
 			field->func.val = func->min;
 		else if (field->len == 1)
-			field->func.val = proto_hdr_field_get_u8(hdr, fid);
+			field->func.val = proto_field_get_u8(field);
 		else if (field->len == 2)
-			field->func.val = proto_hdr_field_get_u16(hdr, fid);
+			field->func.val = proto_field_get_u16(field);
 		else if (field->len == 4)
-			field->func.val = proto_hdr_field_get_u32(hdr, fid);
+			field->func.val = proto_field_get_u32(field);
 		else if (field->len > 4) {
 			uint8_t *bytes = __proto_field_get_bytes(field);
 
diff --git a/trafgen_proto.h b/trafgen_proto.h
index d4427e6..29d68db 100644
--- a/trafgen_proto.h
+++ b/trafgen_proto.h
@@ -66,7 +66,9 @@ struct proto_field_func {
 	uint32_t min;
 	uint32_t max;
 	int32_t inc;
+	uint16_t offset;
 	uint32_t val;
+	size_t len;
 
 	void (*update_field)(struct proto_field *field);
 };
@@ -142,9 +144,6 @@ extern void proto_hdr_field_set_default_dev_ipv6(struct proto_hdr *hdr, uint32_t
 
 extern void proto_field_dyn_apply(struct proto_field *field);
 
-extern void proto_hdr_field_func_add(struct proto_hdr *hdr, uint32_t fid,
-				     struct proto_field_func *func);
-
 extern struct proto_field *proto_hdr_field_by_id(struct proto_hdr *hdr, uint32_t fid);
 
 
@@ -157,4 +156,7 @@ extern uint32_t proto_field_get_u32(struct proto_field *field);
 extern void proto_field_set_be16(struct proto_field *field, uint16_t val);
 extern void proto_field_set_be32(struct proto_field *field, uint32_t val);
 
+extern void proto_field_func_add(struct proto_field *field,
+				 struct proto_field_func *func);
+
 #endif /* TRAFGEN_PROTO_H */