[PATCH V3 4/4] pipeline: support packet recirculation

[Cristian Dumitrescu <cristian.dumitrescu@intel.com>]

Add support for packet recirculation. The current packet is flagged
for recirculation using the new "recirculate" instruction; on TX, this
flag causes the packet to execute the full pipeline again as if it was
a new packet, except the packet meta-data is preserved. The new
"recircid" instruction can be used to read the pass number in case the
packet goes several times through the pipeline.

Signed-off-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
---
 lib/pipeline/rte_swx_pipeline.c          | 112 +++++++++++++++++++++++
 lib/pipeline/rte_swx_pipeline_internal.h |  62 ++++++++++++-
 2 files changed, 172 insertions(+), 2 deletions(-)

diff --git a/lib/pipeline/rte_swx_pipeline.c b/lib/pipeline/rte_swx_pipeline.c
index 062fbcfc89..17da11c015 100644
--- a/lib/pipeline/rte_swx_pipeline.c
+++ b/lib/pipeline/rte_swx_pipeline.c
@@ -1782,6 +1782,68 @@ instr_mirror_exec(struct rte_swx_pipeline *p)
 	thread_ip_inc(p);
 }
 
+/*
+ * recirculate.
+ */
+static int
+instr_recirculate_translate(struct rte_swx_pipeline *p __rte_unused,
+			    struct action *action __rte_unused,
+			    char **tokens __rte_unused,
+			    int n_tokens,
+			    struct instruction *instr,
+			    struct instruction_data *data __rte_unused)
+{
+	CHECK(n_tokens == 1, EINVAL);
+
+	instr->type = INSTR_RECIRCULATE;
+	return 0;
+}
+
+static int
+instr_recircid_translate(struct rte_swx_pipeline *p,
+			 struct action *action __rte_unused,
+			 char **tokens,
+			 int n_tokens,
+			 struct instruction *instr,
+			 struct instruction_data *data __rte_unused)
+{
+	struct field *f;
+
+	CHECK(n_tokens == 2, EINVAL);
+
+	f = metadata_field_parse(p, tokens[1]);
+	CHECK(f, EINVAL);
+
+	instr->type = INSTR_RECIRCID;
+	instr->io.io.offset = f->offset / 8;
+	instr->io.io.n_bits = f->n_bits;
+	return 0;
+}
+
+static inline void
+instr_recirculate_exec(struct rte_swx_pipeline *p)
+{
+	struct thread *t = &p->threads[p->thread_id];
+	struct instruction *ip = t->ip;
+
+	__instr_recirculate_exec(p, t, ip);
+
+	/* Thread. */
+	thread_ip_inc(p);
+}
+
+static inline void
+instr_recircid_exec(struct rte_swx_pipeline *p)
+{
+	struct thread *t = &p->threads[p->thread_id];
+	struct instruction *ip = t->ip;
+
+	__instr_recircid_exec(p, t, ip);
+
+	/* Thread. */
+	thread_ip_inc(p);
+}
+
 /*
  * extract.
  */
@@ -5790,6 +5852,22 @@ instr_translate(struct rte_swx_pipeline *p,
 					      instr,
 					      data);
 
+	if (!strcmp(tokens[tpos], "recirculate"))
+		return instr_recirculate_translate(p,
+					      action,
+					      &tokens[tpos],
+					      n_tokens - tpos,
+					      instr,
+					      data);
+
+	if (!strcmp(tokens[tpos], "recircid"))
+		return instr_recircid_translate(p,
+					      action,
+					      &tokens[tpos],
+					      n_tokens - tpos,
+					      instr,
+					      data);
+
 	if (!strcmp(tokens[tpos], "extract"))
 		return instr_hdr_extract_translate(p,
 						   action,
@@ -6815,6 +6893,8 @@ static instr_exec_t instruction_table[] = {
 	[INSTR_TX_I] = instr_tx_i_exec,
 	[INSTR_DROP] = instr_drop_exec,
 	[INSTR_MIRROR] = instr_mirror_exec,
+	[INSTR_RECIRCULATE] = instr_recirculate_exec,
+	[INSTR_RECIRCID] = instr_recircid_exec,
 
 	[INSTR_HDR_EXTRACT] = instr_hdr_extract_exec,
 	[INSTR_HDR_EXTRACT2] = instr_hdr_extract2_exec,
@@ -10223,6 +10303,8 @@ instr_type_to_name(struct instruction *instr)
 	case INSTR_TX_I: return "INSTR_TX_I";
 	case INSTR_DROP: return "INSTR_DROP";
 	case INSTR_MIRROR: return "INSTR_MIRROR";
+	case INSTR_RECIRCULATE: return "INSTR_RECIRCULATE";
+	case INSTR_RECIRCID: return "INSTR_RECIRCID";
 
 	case INSTR_HDR_EXTRACT: return "INSTR_HDR_EXTRACT";
 	case INSTR_HDR_EXTRACT2: return "INSTR_HDR_EXTRACT2";
@@ -10553,6 +10635,32 @@ instr_mirror_export(struct instruction *instr, FILE *f)
 		instr->mirror.src.offset);
 }
 
+static void
+instr_recirculate_export(struct instruction *instr, FILE *f)
+{
+	fprintf(f,
+		"\t{\n"
+		"\t\t.type = %s,\n"
+		"\t},\n",
+		instr_type_to_name(instr));
+}
+
+static void
+instr_recircid_export(struct instruction *instr, FILE *f)
+{
+	fprintf(f,
+		"\t{\n"
+		"\t\t.type = %s,\n"
+		"\t\t.io = {\n"
+		"\t\t\t.offset = %u,\n"
+		"\t\t\t.n_bits = %u,\n"
+		"\t\t},\n"
+		"\t},\n",
+		instr_type_to_name(instr),
+		instr->io.io.offset,
+		instr->io.io.n_bits);
+}
+
 static void
 instr_hdr_validate_export(struct instruction *instr, FILE *f)
 {
@@ -11121,6 +11229,8 @@ static instruction_export_t export_table[] = {
 	[INSTR_TX_I] = instr_io_export,
 	[INSTR_DROP] = instr_io_export,
 	[INSTR_MIRROR] = instr_mirror_export,
+	[INSTR_RECIRCULATE] = instr_recirculate_export,
+	[INSTR_RECIRCID] = instr_recircid_export,
 
 	[INSTR_HDR_EXTRACT] = instr_io_export,
 	[INSTR_HDR_EXTRACT2] = instr_io_export,
@@ -11340,6 +11450,8 @@ instr_type_to_func(struct instruction *instr)
 	case INSTR_TX_I: return "__instr_tx_i_exec";
 	case INSTR_DROP: return "__instr_drop_exec";
 	case INSTR_MIRROR: return "__instr_mirror_exec";
+	case INSTR_RECIRCULATE: return "__instr_recirculate_exec";
+	case INSTR_RECIRCID: return "__instr_recircid_exec";
 
 	case INSTR_HDR_EXTRACT: return "__instr_hdr_extract_exec";
 	case INSTR_HDR_EXTRACT2: return "__instr_hdr_extract2_exec";
diff --git a/lib/pipeline/rte_swx_pipeline_internal.h b/lib/pipeline/rte_swx_pipeline_internal.h
index 808a0cbdbb..156ac27d6f 100644
--- a/lib/pipeline/rte_swx_pipeline_internal.h
+++ b/lib/pipeline/rte_swx_pipeline_internal.h
@@ -245,6 +245,15 @@ enum instruction_type {
 	 */
 	INSTR_MIRROR,
 
+	/* recirculate
+	 */
+	INSTR_RECIRCULATE,
+
+	/* recircid m.recirc_pass_id
+	 * Read the internal recirculation pass ID into the specified meta-data field.
+	 */
+	INSTR_RECIRCID,
+
 	/* extract h.header */
 	INSTR_HDR_EXTRACT,
 	INSTR_HDR_EXTRACT2,
@@ -923,6 +932,8 @@ struct thread {
 	uint8_t *ptr;
 	uint32_t *mirroring_slots;
 	uint64_t mirroring_slots_mask;
+	int recirculate;
+	uint32_t recirc_pass_id;
 
 	/* Structures. */
 	uint8_t **structs;
@@ -1525,6 +1536,27 @@ __instr_rx_exec(struct rte_swx_pipeline *p, struct thread *t, const struct instr
 	struct rte_swx_pkt *pkt = &t->pkt;
 	int pkt_received;
 
+	/* Recirculation: keep the current packet. */
+	if (t->recirculate) {
+		TRACE("[Thread %2u] rx (recirculate pass %u)\n",
+		      p->thread_id,
+		      t->recirc_pass_id);
+
+		/* Packet. */
+		t->mirroring_slots_mask = 0;
+		t->recirculate = 0;
+		t->recirc_pass_id++;
+
+		/* Headers. */
+		t->valid_headers = 0;
+		t->n_headers_out = 0;
+
+		/* Tables. */
+		t->table_state = p->table_state;
+
+		return 1;
+	}
+
 	/* Packet. */
 	pkt_received = port->pkt_rx(port->obj, pkt);
 	t->ptr = &pkt->pkt[pkt->offset];
@@ -1536,6 +1568,7 @@ __instr_rx_exec(struct rte_swx_pipeline *p, struct thread *t, const struct instr
 	      p->port_id);
 
 	t->mirroring_slots_mask = 0;
+	t->recirc_pass_id = 0;
 
 	/* Headers. */
 	t->valid_headers = 0;
@@ -1665,7 +1698,8 @@ __instr_tx_exec(struct rte_swx_pipeline *p, struct thread *t, const struct instr
 
 	/* Packet. */
 	mirroring_handler(p, t, pkt);
-	port->pkt_tx(port->obj, pkt);
+	if (!t->recirculate)
+		port->pkt_tx(port->obj, pkt);
 }
 
 static inline void
@@ -1684,7 +1718,8 @@ __instr_tx_i_exec(struct rte_swx_pipeline *p, struct thread *t, const struct ins
 
 	/* Packet. */
 	mirroring_handler(p, t, pkt);
-	port->pkt_tx(port->obj, pkt);
+	if (!t->recirculate)
+		port->pkt_tx(port->obj, pkt);
 }
 
 static inline void
@@ -1727,6 +1762,29 @@ __instr_mirror_exec(struct rte_swx_pipeline *p,
 	t->mirroring_slots_mask |= 1LLU << slot_id;
 }
 
+static inline void
+__instr_recirculate_exec(struct rte_swx_pipeline *p __rte_unused,
+			 struct thread *t,
+			 const struct instruction *ip __rte_unused)
+{
+	TRACE("[Thread %2u]: recirculate\n",
+	      p->thread_id);
+
+	t->recirculate = 1;
+}
+
+static inline void
+__instr_recircid_exec(struct rte_swx_pipeline *p __rte_unused,
+		      struct thread *t,
+		      const struct instruction *ip)
+{
+	TRACE("[Thread %2u]: recircid\n",
+	      p->thread_id);
+
+	/* Meta-data. */
+	METADATA_WRITE(t, ip->io.io.offset, ip->io.io.n_bits, t->recirc_pass_id);
+}
+
 /*
  * extract.
  */
-- 
2.17.1