[PATCH v8 3/8] net/tap: validate and setup parameters for BPF RSS

[Stephen Hemminger <stephen@networkplumber.org>]

The flow RSS support via BPF was not using the key, or
hash type parameters. Which is good because they were never
properly setup.

Fix the setup and validate the flow parameters, the BPF
side gets fixed later.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/tap/tap_flow.c | 65 +++++++++++++++++++++++++++++++++++---
 drivers/net/tap/tap_rss.h  |  5 ++-
 2 files changed, 62 insertions(+), 8 deletions(-)

diff --git a/drivers/net/tap/tap_flow.c b/drivers/net/tap/tap_flow.c
index 8fccd599f0..8cf64364a7 100644
--- a/drivers/net/tap/tap_flow.c
+++ b/drivers/net/tap/tap_flow.c
@@ -11,9 +11,11 @@
 
 #include <rte_byteorder.h>
 #include <rte_jhash.h>
+#include <rte_thash.h>
 #include <rte_random.h>
 #include <rte_malloc.h>
 #include <rte_eth_tap.h>
+
 #include <tap_flow.h>
 #include <tap_autoconf.h>
 #include <tap_tcmsgs.h>
@@ -2061,6 +2063,21 @@ static int bpf_rss_key(enum bpf_rss_key_e cmd, __u32 *key_idx)
 	return err;
 }
 
+
+/* Default RSS hash key also used by mlx devices */
+static const uint8_t rss_hash_default_key[] = {
+	0x2c, 0xc6, 0x81, 0xd1,
+	0x5b, 0xdb, 0xf4, 0xf7,
+	0xfc, 0xa2, 0x83, 0x19,
+	0xdb, 0x1a, 0x3e, 0x94,
+	0x6b, 0x9e, 0x38, 0xd9,
+	0x2c, 0x9c, 0x03, 0xd1,
+	0xad, 0x99, 0x44, 0xa7,
+	0xd9, 0x56, 0x3d, 0x59,
+	0x06, 0x3c, 0x25, 0xf3,
+	0xfc, 0x1f, 0xdc, 0x2a,
+};
+
 /**
  * Add RSS hash calculations and queue selection
  *
@@ -2079,11 +2096,11 @@ static int rss_add_actions(struct rte_flow *flow, struct pmd_internals *pmd,
 			   const struct rte_flow_action_rss *rss,
 			   struct rte_flow_error *error)
 {
-	/* 4096 is the maximum number of instructions for a BPF program */
+	struct rss_key rss_entry = { };
+	const uint8_t *key_in;
+	uint32_t hash_type = 0;
 	unsigned int i;
 	int err;
-	struct rss_key rss_entry = { .hash_fields = 0,
-				     .key_size = 0 };
 
 	/* Check supported RSS features */
 	if (rss->func != RTE_ETH_HASH_FUNCTION_DEFAULT)
@@ -2095,6 +2112,41 @@ static int rss_add_actions(struct rte_flow *flow, struct pmd_internals *pmd,
 			(error, ENOTSUP, RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
 			 "a nonzero RSS encapsulation level is not supported");
 
+	if (rss->queue_num == 0 || rss->queue_num >= TAP_MAX_QUEUES)
+		return rte_flow_error_set(error, EINVAL, RTE_FLOW_ERROR_TYPE_UNSPECIFIED, NULL,
+					  "invalid number of queues");
+
+	/* allow RSS key_len 0 in case of NULL (default) RSS key. */
+	if (rss->key_len == 0) {
+		if (rss->key != NULL)
+			return rte_flow_error_set(error, ENOTSUP,
+						  RTE_FLOW_ERROR_TYPE_ACTION_CONF,
+						  &rss->key_len, "RSS hash key length 0");
+		key_in = rss_hash_default_key;
+	} else {
+		if (rss->key_len != TAP_RSS_HASH_KEY_SIZE)
+			return rte_flow_error_set(error, EINVAL, RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+						  NULL, "RSS hash invalid key length");
+		if (rss->key == NULL)
+			return rte_flow_error_set(error, EINVAL, RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+						  NULL, "RSS hash key is NULL");
+		key_in = rss->key;
+	}
+
+	if (rss->types & TAP_RSS_HF_MASK)
+		return rte_flow_error_set(error, EINVAL, RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
+					  NULL, "RSS hash type not supported");
+
+	if (rss->types & (RTE_ETH_RSS_NONFRAG_IPV4_UDP | RTE_ETH_RSS_NONFRAG_IPV4_TCP))
+		hash_type |= RTE_BIT32(HASH_FIELD_IPV4_L3_L4);
+	else if (rss->types & (RTE_ETH_RSS_IPV4 | RTE_ETH_RSS_FRAG_IPV4))
+		hash_type |= RTE_BIT32(HASH_FIELD_IPV4_L3);
+
+	if (rss->types & (RTE_ETH_RSS_NONFRAG_IPV6_UDP | RTE_ETH_RSS_NONFRAG_IPV6_TCP))
+		hash_type |= RTE_BIT32(HASH_FIELD_IPV6_L3_L4);
+	else if (rss->types & (RTE_ETH_RSS_IPV6 | RTE_ETH_RSS_FRAG_IPV6 | RTE_ETH_RSS_IPV6_EX))
+		hash_type |= RTE_BIT32(HASH_FIELD_IPV6_L3);
+
 	/* Get a new map key for a new RSS rule */
 	err = bpf_rss_key(KEY_CMD_GET, &flow->key_idx);
 	if (err < 0) {
@@ -2109,8 +2161,11 @@ static int rss_add_actions(struct rte_flow *flow, struct pmd_internals *pmd,
 	rss_entry.nb_queues = rss->queue_num;
 	for (i = 0; i < rss->queue_num; i++)
 		rss_entry.queues[i] = rss->queue[i];
-	rss_entry.hash_fields =
-		(1 << HASH_FIELD_IPV4_L3_L4) | (1 << HASH_FIELD_IPV6_L3_L4);
+
+	rss_entry.hash_fields = hash_type;
+	rte_convert_rss_key((const uint32_t *)key_in, (uint32_t *)rss_entry.key,
+			    TAP_RSS_HASH_KEY_SIZE);
+
 
 	/* Add this RSS entry to map */
 	err = tap_flow_bpf_update_rss_elem(pmd->map_fd,
diff --git a/drivers/net/tap/tap_rss.h b/drivers/net/tap/tap_rss.h
index 8766ffc244..6009be7031 100644
--- a/drivers/net/tap/tap_rss.h
+++ b/drivers/net/tap/tap_rss.h
@@ -24,11 +24,10 @@ enum hash_field {
 };
 
 struct rss_key {
-	 __u8 key[128];
 	__u32 hash_fields;
-	__u32 key_size;
-	__u32 queues[TAP_MAX_QUEUES];
+	__u8 key[TAP_RSS_HASH_KEY_SIZE];
 	__u32 nb_queues;
+	__u32 queues[TAP_MAX_QUEUES];
 } __attribute__((packed));
 
 #endif /* _TAP_RSS_H_ */
-- 
2.43.0