diff --git a/lib/librte_pipeline/rte_pipeline_version.map b/lib/librte_pipeline/rte_pipeline_version.map
index 88fd38ca8..6a48c3666 100644
--- a/lib/librte_pipeline/rte_pipeline_version.map
+++ b/lib/librte_pipeline/rte_pipeline_version.map
@@ -60,6 +60,9 @@ EXPERIMENTAL {
 	rte_swx_pipeline_port_in_config;
 	rte_swx_pipeline_port_out_type_register;
 	rte_swx_pipeline_port_out_config;
+	rte_swx_pipeline_struct_type_register;
+	rte_swx_pipeline_packet_header_register;
+	rte_swx_pipeline_packet_metadata_register;
 	rte_swx_pipeline_build;
 	rte_swx_pipeline_free;
 };
diff --git a/lib/librte_pipeline/rte_swx_pipeline.c b/lib/librte_pipeline/rte_swx_pipeline.c
index 7aeac8cc8..cb2e32b83 100644
--- a/lib/librte_pipeline/rte_swx_pipeline.c
+++ b/lib/librte_pipeline/rte_swx_pipeline.c
@@ -20,6 +20,25 @@ do {                                                                           \
 #define CHECK_NAME(name, err_code)                                             \
 	CHECK((name) && (name)[0], err_code)
 
+/*
+ * Struct.
+ */
+struct field {
+	char name[RTE_SWX_NAME_SIZE];
+	uint32_t n_bits;
+	uint32_t offset;
+};
+
+struct struct_type {
+	TAILQ_ENTRY(struct_type) node;
+	char name[RTE_SWX_NAME_SIZE];
+	struct field *fields;
+	uint32_t n_fields;
+	uint32_t n_bits;
+};
+
+TAILQ_HEAD(struct_type_tailq, struct_type);
+
 /*
  * Input port.
  */
@@ -71,24 +90,198 @@ struct port_out_runtime {
 	void *obj;
 };
 
+/*
+ * Header.
+ */
+struct header {
+	TAILQ_ENTRY(header) node;
+	char name[RTE_SWX_NAME_SIZE];
+	struct struct_type *st;
+	uint32_t struct_id;
+	uint32_t id;
+};
+
+TAILQ_HEAD(header_tailq, header);
+
+struct header_runtime {
+	uint8_t *ptr0;
+};
+
+struct header_out_runtime {
+	uint8_t *ptr0;
+	uint8_t *ptr;
+	uint32_t n_bytes;
+};
+
 /*
  * Pipeline.
  */
+struct thread {
+	/* Structures. */
+	uint8_t **structs;
+
+	/* Packet headers. */
+	struct header_runtime *headers; /* Extracted or generated headers. */
+	struct header_out_runtime *headers_out; /* Emitted headers. */
+	uint8_t *header_storage;
+	uint8_t *header_out_storage;
+	uint64_t valid_headers;
+	uint32_t n_headers_out;
+
+	/* Packet meta-data. */
+	uint8_t *metadata;
+};
+
+#ifndef RTE_SWX_PIPELINE_THREADS_MAX
+#define RTE_SWX_PIPELINE_THREADS_MAX 16
+#endif
+
 struct rte_swx_pipeline {
+	struct struct_type_tailq struct_types;
 	struct port_in_type_tailq port_in_types;
 	struct port_in_tailq ports_in;
 	struct port_out_type_tailq port_out_types;
 	struct port_out_tailq ports_out;
+	struct header_tailq headers;
+	struct struct_type *metadata_st;
+	uint32_t metadata_struct_id;
 
 	struct port_in_runtime *in;
 	struct port_out_runtime *out;
+	struct thread threads[RTE_SWX_PIPELINE_THREADS_MAX];
 
+	uint32_t n_structs;
 	uint32_t n_ports_in;
 	uint32_t n_ports_out;
+	uint32_t n_headers;
 	int build_done;
 	int numa_node;
 };
 
+/*
+ * Struct.
+ */
+static struct struct_type *
+struct_type_find(struct rte_swx_pipeline *p, const char *name)
+{
+	struct struct_type *elem;
+
+	TAILQ_FOREACH(elem, &p->struct_types, node)
+		if (strcmp(elem->name, name) == 0)
+			return elem;
+
+	return NULL;
+}
+
+int
+rte_swx_pipeline_struct_type_register(struct rte_swx_pipeline *p,
+				      const char *name,
+				      struct rte_swx_field_params *fields,
+				      uint32_t n_fields)
+{
+	struct struct_type *st;
+	uint32_t i;
+
+	CHECK(p, EINVAL);
+	CHECK_NAME(name, EINVAL);
+	CHECK(fields, EINVAL);
+	CHECK(n_fields, EINVAL);
+
+	for (i = 0; i < n_fields; i++) {
+		struct rte_swx_field_params *f = &fields[i];
+		uint32_t j;
+
+		CHECK_NAME(f->name, EINVAL);
+		CHECK(f->n_bits, EINVAL);
+		CHECK(f->n_bits <= 64, EINVAL);
+		CHECK((f->n_bits & 7) == 0, EINVAL);
+
+		for (j = 0; j < i; j++) {
+			struct rte_swx_field_params *f_prev = &fields[j];
+
+			CHECK(strcmp(f->name, f_prev->name), EINVAL);
+		}
+	}
+
+	CHECK(!struct_type_find(p, name), EEXIST);
+
+	/* Node allocation. */
+	st = calloc(1, sizeof(struct struct_type));
+	CHECK(st, ENOMEM);
+
+	st->fields = calloc(n_fields, sizeof(struct field));
+	if (!st->fields) {
+		free(st);
+		CHECK(0, ENOMEM);
+	}
+
+	/* Node initialization. */
+	strcpy(st->name, name);
+	for (i = 0; i < n_fields; i++) {
+		struct field *dst = &st->fields[i];
+		struct rte_swx_field_params *src = &fields[i];
+
+		strcpy(dst->name, src->name);
+		dst->n_bits = src->n_bits;
+		dst->offset = st->n_bits;
+
+		st->n_bits += src->n_bits;
+	}
+	st->n_fields = n_fields;
+
+	/* Node add to tailq. */
+	TAILQ_INSERT_TAIL(&p->struct_types, st, node);
+
+	return 0;
+}
+
+static int
+struct_build(struct rte_swx_pipeline *p)
+{
+	uint32_t i;
+
+	for (i = 0; i < RTE_SWX_PIPELINE_THREADS_MAX; i++) {
+		struct thread *t = &p->threads[i];
+
+		t->structs = calloc(p->n_structs, sizeof(uint8_t *));
+		CHECK(t->structs, ENOMEM);
+	}
+
+	return 0;
+}
+
+static void
+struct_build_free(struct rte_swx_pipeline *p)
+{
+	uint32_t i;
+
+	for (i = 0; i < RTE_SWX_PIPELINE_THREADS_MAX; i++) {
+		struct thread *t = &p->threads[i];
+
+		free(t->structs);
+		t->structs = NULL;
+	}
+}
+
+static void
+struct_free(struct rte_swx_pipeline *p)
+{
+	struct_build_free(p);
+
+	/* Struct types. */
+	for ( ; ; ) {
+		struct struct_type *elem;
+
+		elem = TAILQ_FIRST(&p->struct_types);
+		if (!elem)
+			break;
+
+		TAILQ_REMOVE(&p->struct_types, elem, node);
+		free(elem->fields);
+		free(elem);
+	}
+}
+
 /*
  * Input port.
  */
@@ -413,6 +606,205 @@ port_out_free(struct rte_swx_pipeline *p)
 	}
 }
 
+/*
+ * Header.
+ */
+static struct header *
+header_find(struct rte_swx_pipeline *p, const char *name)
+{
+	struct header *elem;
+
+	TAILQ_FOREACH(elem, &p->headers, node)
+		if (strcmp(elem->name, name) == 0)
+			return elem;
+
+	return NULL;
+}
+
+int
+rte_swx_pipeline_packet_header_register(struct rte_swx_pipeline *p,
+					const char *name,
+					const char *struct_type_name)
+{
+	struct struct_type *st;
+	struct header *h;
+	size_t n_headers_max;
+
+	CHECK(p, EINVAL);
+	CHECK_NAME(name, EINVAL);
+	CHECK_NAME(struct_type_name, EINVAL);
+
+	CHECK(!header_find(p, name), EEXIST);
+
+	st = struct_type_find(p, struct_type_name);
+	CHECK(st, EINVAL);
+
+	n_headers_max = RTE_SIZEOF_FIELD(struct thread, valid_headers) * 8;
+	CHECK(p->n_headers < n_headers_max, ENOSPC);
+
+	/* Node allocation. */
+	h = calloc(1, sizeof(struct header));
+	CHECK(h, ENOMEM);
+
+	/* Node initialization. */
+	strcpy(h->name, name);
+	h->st = st;
+	h->struct_id = p->n_structs;
+	h->id = p->n_headers;
+
+	/* Node add to tailq. */
+	TAILQ_INSERT_TAIL(&p->headers, h, node);
+	p->n_headers++;
+	p->n_structs++;
+
+	return 0;
+}
+
+static int
+header_build(struct rte_swx_pipeline *p)
+{
+	struct header *h;
+	uint32_t n_bytes = 0, i;
+
+	TAILQ_FOREACH(h, &p->headers, node) {
+		n_bytes += h->st->n_bits / 8;
+	}
+
+	for (i = 0; i < RTE_SWX_PIPELINE_THREADS_MAX; i++) {
+		struct thread *t = &p->threads[i];
+		uint32_t offset = 0;
+
+		t->headers = calloc(p->n_headers,
+				    sizeof(struct header_runtime));
+		CHECK(t->headers, ENOMEM);
+
+		t->headers_out = calloc(p->n_headers,
+					sizeof(struct header_out_runtime));
+		CHECK(t->headers_out, ENOMEM);
+
+		t->header_storage = calloc(1, n_bytes);
+		CHECK(t->header_storage, ENOMEM);
+
+		t->header_out_storage = calloc(1, n_bytes);
+		CHECK(t->header_out_storage, ENOMEM);
+
+		TAILQ_FOREACH(h, &p->headers, node) {
+			uint8_t *header_storage;
+
+			header_storage = &t->header_storage[offset];
+			offset += h->st->n_bits / 8;
+
+			t->headers[h->id].ptr0 = header_storage;
+			t->structs[h->struct_id] = header_storage;
+		}
+	}
+
+	return 0;
+}
+
+static void
+header_build_free(struct rte_swx_pipeline *p)
+{
+	uint32_t i;
+
+	for (i = 0; i < RTE_SWX_PIPELINE_THREADS_MAX; i++) {
+		struct thread *t = &p->threads[i];
+
+		free(t->headers_out);
+		t->headers_out = NULL;
+
+		free(t->headers);
+		t->headers = NULL;
+
+		free(t->header_out_storage);
+		t->header_out_storage = NULL;
+
+		free(t->header_storage);
+		t->header_storage = NULL;
+	}
+}
+
+static void
+header_free(struct rte_swx_pipeline *p)
+{
+	header_build_free(p);
+
+	for ( ; ; ) {
+		struct header *elem;
+
+		elem = TAILQ_FIRST(&p->headers);
+		if (!elem)
+			break;
+
+		TAILQ_REMOVE(&p->headers, elem, node);
+		free(elem);
+	}
+}
+
+/*
+ * Meta-data.
+ */
+int
+rte_swx_pipeline_packet_metadata_register(struct rte_swx_pipeline *p,
+					  const char *struct_type_name)
+{
+	struct struct_type *st = NULL;
+
+	CHECK(p, EINVAL);
+
+	CHECK_NAME(struct_type_name, EINVAL);
+	st  = struct_type_find(p, struct_type_name);
+	CHECK(st, EINVAL);
+	CHECK(!p->metadata_st, EINVAL);
+
+	p->metadata_st = st;
+	p->metadata_struct_id = p->n_structs;
+
+	p->n_structs++;
+
+	return 0;
+}
+
+static int
+metadata_build(struct rte_swx_pipeline *p)
+{
+	uint32_t n_bytes = p->metadata_st->n_bits / 8;
+	uint32_t i;
+
+	/* Thread-level initialization. */
+	for (i = 0; i < RTE_SWX_PIPELINE_THREADS_MAX; i++) {
+		struct thread *t = &p->threads[i];
+		uint8_t *metadata;
+
+		metadata = calloc(1, n_bytes);
+		CHECK(metadata, ENOMEM);
+
+		t->metadata = metadata;
+		t->structs[p->metadata_struct_id] = metadata;
+	}
+
+	return 0;
+}
+
+static void
+metadata_build_free(struct rte_swx_pipeline *p)
+{
+	uint32_t i;
+
+	for (i = 0; i < RTE_SWX_PIPELINE_THREADS_MAX; i++) {
+		struct thread *t = &p->threads[i];
+
+		free(t->metadata);
+		t->metadata = NULL;
+	}
+}
+
+static void
+metadata_free(struct rte_swx_pipeline *p)
+{
+	metadata_build_free(p);
+}
+
 /*
  * Pipeline.
  */
@@ -429,11 +821,14 @@ rte_swx_pipeline_config(struct rte_swx_pipeline **p, int numa_node)
 	CHECK(pipeline, ENOMEM);
 
 	/* Initialization. */
+	TAILQ_INIT(&pipeline->struct_types);
 	TAILQ_INIT(&pipeline->port_in_types);
 	TAILQ_INIT(&pipeline->ports_in);
 	TAILQ_INIT(&pipeline->port_out_types);
 	TAILQ_INIT(&pipeline->ports_out);
+	TAILQ_INIT(&pipeline->headers);
 
+	pipeline->n_structs = 1; /* Struct 0 is reserved for action_data. */
 	pipeline->numa_node = numa_node;
 
 	*p = pipeline;
@@ -446,8 +841,11 @@ rte_swx_pipeline_free(struct rte_swx_pipeline *p)
 	if (!p)
 		return;
 
+	metadata_free(p);
+	header_free(p);
 	port_out_free(p);
 	port_in_free(p);
+	struct_free(p);
 
 	free(p);
 }
@@ -468,12 +866,27 @@ rte_swx_pipeline_build(struct rte_swx_pipeline *p)
 	if (status)
 		goto error;
 
+	status = struct_build(p);
+	if (status)
+		goto error;
+
+	status = header_build(p);
+	if (status)
+		goto error;
+
+	status = metadata_build(p);
+	if (status)
+		goto error;
+
 	p->build_done = 1;
 	return 0;
 
 error:
+	metadata_build_free(p);
+	header_build_free(p);
 	port_out_build_free(p);
 	port_in_build_free(p);
+	struct_build_free(p);
 
 	return status;
 }
diff --git a/lib/librte_pipeline/rte_swx_pipeline.h b/lib/librte_pipeline/rte_swx_pipeline.h
index 2be83bd35..4a7b679a4 100644
--- a/lib/librte_pipeline/rte_swx_pipeline.h
+++ b/lib/librte_pipeline/rte_swx_pipeline.h
@@ -147,6 +147,91 @@ rte_swx_pipeline_port_out_config(struct rte_swx_pipeline *p,
 				 const char *port_type_name,
 				 void *args);
 
+/*
+ * Packet headers and meta-data
+ */
+
+/** Structure (struct) field. */
+struct rte_swx_field_params {
+	/** Struct field name. */
+	const char *name;
+
+	/** Struct field size (in bits).
+	 * Restriction: All struct fields must be a multiple of 8 bits.
+	 * Restriction: All struct fields must be no greater than 64 bits.
+	 */
+	uint32_t n_bits;
+};
+
+/**
+ * Pipeline struct type register
+ *
+ * Structs are used extensively in many part of the pipeline to define the size
+ * and layout of a specific memory piece such as: headers, meta-data, action
+ * data stored in a table entry, mailboxes for extern objects and functions.
+ * Similar to C language structs, they are a well defined sequence of fields,
+ * with each field having a unique name and a constant size.
+ *
+ * @param[in] p
+ *   Pipeline handle.
+ * @param[in] name
+ *   Struct type name.
+ * @param[in] fields
+ *   The sequence of struct fields.
+ * @param[in] n_fields
+ *   The number of struct fields.
+ * @return
+ *   0 on success or the following error codes otherwise:
+ *   -EINVAL: Invalid argument;
+ *   -ENOMEM: Not enough space/cannot allocate memory;
+ *   -EEXIST: Struct type with this name already exists.
+ */
+__rte_experimental
+int
+rte_swx_pipeline_struct_type_register(struct rte_swx_pipeline *p,
+				      const char *name,
+				      struct rte_swx_field_params *fields,
+				      uint32_t n_fields);
+
+/**
+ * Pipeline packet header register
+ *
+ * @param[in] p
+ *   Pipeline handle.
+ * @param[in] name
+ *   Header name.
+ * @param[in] struct_type_name
+ *   The struct type instantiated by this packet header.
+ * @return
+ *   0 on success or the following error codes otherwise:
+ *   -EINVAL: Invalid argument;
+ *   -ENOMEM: Not enough space/cannot allocate memory;
+ *   -EEXIST: Header with this name already exists;
+ *   -ENOSPC: Maximum number of headers reached for the pipeline.
+ */
+__rte_experimental
+int
+rte_swx_pipeline_packet_header_register(struct rte_swx_pipeline *p,
+					const char *name,
+					const char *struct_type_name);
+
+/**
+ * Pipeline packet meta-data register
+ *
+ * @param[in] p
+ *   Pipeline handle.
+ * @param[in] struct_type_name
+ *   The struct type instantiated by the packet meta-data.
+ * @return
+ *   0 on success or the following error codes otherwise:
+ *   -EINVAL: Invalid argument.
+ */
+__rte_experimental
+int
+rte_swx_pipeline_packet_metadata_register(struct rte_swx_pipeline *p,
+					  const char *struct_type_name);
+
+
 /**
  * Pipeline build
  *
