[dpdk-dev] [PATCH 1/2] acl: fix 32-bit range field doesn't work properly

[Konstantin Ananyev <konstantin.ananyev@intel.com>]

ACL build phase for range fields that are bigger then
16 bits might generate wrong trie.
For more details please refer to:
https://bugs.dpdk.org/show_bug.cgi?id=307

Fixes: dc276b5780c2 ("acl: new library")
Cc: stable@dpdk.org

Reported-by: Ido Goshen <Ido@cgstowernetworks.com>
Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
---
 lib/librte_acl/acl_bld.c | 148 ++++++++++++++++++++++++++++-----------
 1 file changed, 106 insertions(+), 42 deletions(-)

diff --git a/lib/librte_acl/acl_bld.c b/lib/librte_acl/acl_bld.c
index b06bbe920..0ae143e4e 100644
--- a/lib/librte_acl/acl_bld.c
+++ b/lib/librte_acl/acl_bld.c
@@ -778,9 +778,8 @@ acl_build_reset(struct rte_acl_ctx *ctx)
 }
 
 static void
-acl_gen_range(struct acl_build_context *context,
-	const uint8_t *hi, const uint8_t *lo, int size, int level,
-	struct rte_acl_node *root, struct rte_acl_node *end)
+acl_gen_full_range(struct acl_build_context *context, struct rte_acl_node *root,
+	struct rte_acl_node *end, int size, int level)
 {
 	struct rte_acl_node *node, *prev;
 	uint32_t n;
@@ -788,10 +787,71 @@ acl_gen_range(struct acl_build_context *context,
 	prev = root;
 	for (n = size - 1; n > 0; n--) {
 		node = acl_alloc_node(context, level++);
-		acl_add_ptr_range(context, prev, node, lo[n], hi[n]);
+		acl_add_ptr_range(context, prev, node, 0, UINT8_MAX);
 		prev = node;
 	}
-	acl_add_ptr_range(context, prev, end, lo[0], hi[0]);
+	acl_add_ptr_range(context, prev, end, 0, UINT8_MAX);
+}
+
+static void
+acl_gen_range_mdl(struct acl_build_context *context, struct rte_acl_node *root,
+	struct rte_acl_node *end, uint8_t lo, uint8_t hi, int size, int level)
+{
+	struct rte_acl_node *node;
+
+	node = acl_alloc_node(context, level++);
+	acl_add_ptr_range(context, root, node, lo, hi);
+	acl_gen_full_range(context, node, end, size - 1, level);
+}
+
+static void
+acl_gen_range_low(struct acl_build_context *context, struct rte_acl_node *root,
+	struct rte_acl_node *end, const uint8_t *lo, int size, int level)
+{
+	struct rte_acl_node *node;
+	uint32_t n;
+
+	n = size - 1;
+	if (n == 0) {
+		acl_add_ptr_range(context, root, end, lo[0], UINT8_MAX);
+		return;
+	}
+
+	node = acl_alloc_node(context, level++);
+	acl_add_ptr_range(context, root, node, lo[n], lo[n]);
+
+	/* generate lower-bound sub-trie */
+	acl_gen_range_low(context, node, end, lo, n, level);
+
+	/* generate middle sub-trie */
+	if (n > 1 && lo[n - 1] != UINT8_MAX)
+		acl_gen_range_mdl(context, node, end, lo[n - 1] + 1, UINT8_MAX,
+			n, level);
+}
+
+static void
+acl_gen_range_high(struct acl_build_context *context, struct rte_acl_node *root,
+	struct rte_acl_node *end, const uint8_t *hi, int size, int level)
+{
+	struct rte_acl_node *node;
+	uint32_t n;
+
+	n = size - 1;
+	if (n == 0) {
+		acl_add_ptr_range(context, root, end, 0, hi[0]);
+		return;
+	}
+
+	node = acl_alloc_node(context, level++);
+	acl_add_ptr_range(context, root, node, hi[n], hi[n]);
+
+	/* generate upper-bound sub-trie */
+	acl_gen_range_high(context, node, end, hi, n, level);
+
+	/* generate middle sub-trie */
+	if (n > 1 && hi[n - 1] != 0)
+		acl_gen_range_mdl(context, node, end, 0, hi[n - 1] - 1,
+			n, level);
 }
 
 static struct rte_acl_node *
@@ -799,52 +859,56 @@ acl_gen_range_trie(struct acl_build_context *context,
 	const void *min, const void *max,
 	int size, int level, struct rte_acl_node **pend)
 {
-	int32_t n;
-	struct rte_acl_node *root;
-	const uint8_t *lo = min;
-	const uint8_t *hi = max;
+	int32_t k, n;
+	uint8_t hi_ff, lo_00;
+	struct rte_acl_node *node, *prev, *root;
+	const uint8_t *lo;
+	const uint8_t *hi;
+
+	lo = min;
+	hi = max;
 
-	*pend = acl_alloc_node(context, level+size);
+	*pend = acl_alloc_node(context, level + size);
 	root = acl_alloc_node(context, level++);
+	prev = root;
 
-	if (lo[size - 1] == hi[size - 1]) {
-		acl_gen_range(context, hi, lo, size, level, root, *pend);
-	} else {
-		uint8_t limit_lo[64];
-		uint8_t limit_hi[64];
-		uint8_t hi_ff = UINT8_MAX;
-		uint8_t lo_00 = 0;
+	/* build common sub-trie till possilbe */
+	for (n = size - 1; n > 0 && lo[n] == hi[n]; n--) {
+		node = acl_alloc_node(context, level++);
+		acl_add_ptr_range(context, prev, node, lo[n], hi[n]);
+		prev = node;
+	}
 
-		memset(limit_lo, 0, RTE_DIM(limit_lo));
-		memset(limit_hi, UINT8_MAX, RTE_DIM(limit_hi));
+	/* no branchs needed, just one sub-trie */
+	if (n == 0) {
+		acl_add_ptr_range(context, prev, *pend, lo[0], hi[0]);
+		return root;
+	}
 
-		for (n = size - 2; n >= 0; n--) {
-			hi_ff = (uint8_t)(hi_ff & hi[n]);
-			lo_00 = (uint8_t)(lo_00 | lo[n]);
-		}
+	/* gather information about divirgent paths */
+	lo_00 = 0;
+	hi_ff = UINT8_MAX;
+	for (k = n - 1; k >= 0; k--) {
+		hi_ff &= hi[k];
+		lo_00 |= lo[k];
+	}
 
-		if (hi_ff != UINT8_MAX) {
-			limit_lo[size - 1] = hi[size - 1];
-			acl_gen_range(context, hi, limit_lo, size, level,
-				root, *pend);
-		}
+	/* generate left (lower-bound) sub-trie */
+	if (lo_00 != 0)
+		acl_gen_range_low(context, prev, *pend, lo, n + 1, level);
 
-		if (lo_00 != 0) {
-			limit_hi[size - 1] = lo[size - 1];
-			acl_gen_range(context, limit_hi, lo, size, level,
-				root, *pend);
-		}
+	/* generate right (upper-bound) sub-trie */
+	if (hi_ff != UINT8_MAX)
+		acl_gen_range_high(context, prev, *pend, hi, n + 1, level);
 
-		if (hi[size - 1] - lo[size - 1] > 1 ||
-				lo_00 == 0 ||
-				hi_ff == UINT8_MAX) {
-			limit_lo[size-1] = (uint8_t)(lo[size-1] + (lo_00 != 0));
-			limit_hi[size-1] = (uint8_t)(hi[size-1] -
-				(hi_ff != UINT8_MAX));
-			acl_gen_range(context, limit_hi, limit_lo, size,
-				level, root, *pend);
-		}
+	/* generate sub-trie in the middle */
+	if (lo[n] + 1 != hi[n] || lo_00 == 0 || hi_ff == UINT8_MAX) {
+		lo_00 = lo[n] + (lo_00 != 0);
+		hi_ff = hi[n] - (hi_ff != UINT8_MAX);
+		acl_gen_range_mdl(context, prev, *pend, lo_00, hi_ff,
+			n + 1, level);
 	}
+
 	return root;
 }
 
-- 
2.17.1