[PATCH] pipeline: support checksum for variable size headers

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

Added checksum support for variable size headers such as IPv4 headers
with options.

Signed-off-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
Signed-off-by: Yogesh Jangra <yogesh.jangra@intel.com>
---
 lib/pipeline/rte_swx_pipeline.c          |  3 +--
 lib/pipeline/rte_swx_pipeline_internal.h | 21 +++++++++++----------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/lib/pipeline/rte_swx_pipeline.c b/lib/pipeline/rte_swx_pipeline.c
index 1a50c4bb72..1e18906274 100644
--- a/lib/pipeline/rte_swx_pipeline.c
+++ b/lib/pipeline/rte_swx_pipeline.c
@@ -2908,7 +2908,6 @@ instr_alu_ckadd_translate(struct rte_swx_pipeline *p,
 	/* CKADD_STRUCT, CKADD_STRUCT20. */
 	hsrc = header_parse(p, src);
 	CHECK(hsrc, EINVAL);
-	CHECK(!hsrc->st->var_size, EINVAL);
 
 	instr->type = INSTR_ALU_CKADD_STRUCT;
 	if ((hsrc->st->n_bits / 8) == 20)
@@ -2918,7 +2917,7 @@ instr_alu_ckadd_translate(struct rte_swx_pipeline *p,
 	instr->alu.dst.n_bits = fdst->n_bits;
 	instr->alu.dst.offset = fdst->offset / 8;
 	instr->alu.src.struct_id = (uint8_t)hsrc->struct_id;
-	instr->alu.src.n_bits = hsrc->st->n_bits;
+	instr->alu.src.n_bits = (uint8_t)hsrc->id; /* The src header ID is stored here. */
 	instr->alu.src.offset = 0; /* Unused. */
 	return 0;
 }
diff --git a/lib/pipeline/rte_swx_pipeline_internal.h b/lib/pipeline/rte_swx_pipeline_internal.h
index 2e86383e45..8f057deef9 100644
--- a/lib/pipeline/rte_swx_pipeline_internal.h
+++ b/lib/pipeline/rte_swx_pipeline_internal.h
@@ -309,8 +309,8 @@ enum instruction_type {
 	 * dst = H, src = {H, h.header}
 	 */
 	INSTR_ALU_CKADD_FIELD,    /* src = H */
-	INSTR_ALU_CKADD_STRUCT20, /* src = h.header, with sizeof(header) = 20 */
-	INSTR_ALU_CKADD_STRUCT,   /* src = h.hdeader, with any sizeof(header) */
+	INSTR_ALU_CKADD_STRUCT20, /* src = h.header, with sizeof(header) = 20 bytes. */
+	INSTR_ALU_CKADD_STRUCT,   /* src = h.header, with sizeof(header) any 4-byte multiple. */
 
 	/* cksub dst src
 	 * dst = dst '- src
@@ -2854,6 +2854,7 @@ __instr_alu_ckadd_struct_exec(struct rte_swx_pipeline *p __rte_unused,
 			      struct thread *t,
 			      const struct instruction *ip)
 {
+	uint32_t src_header_id = ip->alu.src.n_bits; /* The src header ID is stored here. */
 	uint8_t *dst_struct, *src_struct;
 	uint16_t *dst16_ptr;
 	uint32_t *src32_ptr;
@@ -2869,26 +2870,26 @@ __instr_alu_ckadd_struct_exec(struct rte_swx_pipeline *p __rte_unused,
 	src_struct = t->structs[ip->alu.src.struct_id];
 	src32_ptr = (uint32_t *)&src_struct[0];
 
-	/* The max number of 32-bit words in a 256-byte header is 8 = 2^3.
-	 * Therefore, in the worst case scenario, a 35-bit number is added to a
-	 * 16-bit number (the input r), so the output r is 36-bit number.
+	/* The max number of 32-bit words in a 32K-byte header is 2^13.
+	 * Therefore, in the worst case scenario, a 45-bit number is added to a
+	 * 16-bit number (the input r), so the output r is 46-bit number.
 	 */
-	for (i = 0; i < ip->alu.src.n_bits / 32; i++, src32_ptr++)
+	for (i = 0; i < t->headers[src_header_id].n_bytes / 4; i++, src32_ptr++)
 		r += *src32_ptr;
 
-	/* The first input is a 16-bit number. The second input is a 20-bit
-	 * number. Their sum is a 21-bit number.
+	/* The first input is a 16-bit number. The second input is a 30-bit
+	 * number. Their sum is a 31-bit number.
 	 */
 	r = (r & 0xFFFF) + (r >> 16);
 
 	/* The first input is a 16-bit number (0 .. 0xFFFF). The second input is
-	 * a 5-bit number (0 .. 31). The sum is a 17-bit number (0 .. 0x1000E).
+	 * a 15-bit number (0 .. 0x7FFF). The sum is a 17-bit number (0 .. 0x17FFE).
 	 */
 	r = (r & 0xFFFF) + (r >> 16);
 
 	/* When the input r is (0 .. 0xFFFF), the output r is equal to the input
 	 * r, so the output is (0 .. 0xFFFF). When the input r is (0x10000 ..
-	 * 0x1001E), the output r is (0 .. 31). So no carry bit can be
+	 * 0x17FFE), the output r is (0 .. 0x7FFF). So no carry bit can be
 	 * generated, therefore the output r is always a 16-bit number.
 	 */
 	r = (r & 0xFFFF) + (r >> 16);
-- 
2.17.1