bnxt_en: Add function to calculate Toeplitz hash

For ntuple filters added by aRFS, the Toeplitz hash calculated by our
NIC is available and is used to store the ntuple filter for quick
retrieval.  In the next patches, user defined ntuple filter support
will be added and we need to calculate the same hash for these
filters.  The same hash function needs to be used so we can detect
duplicates.

Add the function bnxt_toeplitz() to calculate the Toeplitz hash for
user defined ntuple filters.  bnxt_toeplitz() uses the same Toeplitz
key and the same key length as the NIC.

bnxt_get_ntp_filter_idx() is added to return the hash index.  For
aRFS, the hash comes from the NIC.  For user defined ntuple, we call
bnxt_toeplitz() to calculate the hash index.

Reviewed-by: Andy Gospodarek <[email protected]>
Signed-off-by: Pavan Chebbi <[email protected]>
Signed-off-by: Michael Chan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Pavan Chebbi

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -4199,13 +4199,22 @@ static void bnxt_init_vnics(struct bnxt *bp)
 		vnic->fw_l2_ctx_id = INVALID_HW_RING_ID;
 
 		if (bp->vnic_info[i].rss_hash_key) {
-			if (i == 0)
+			if (!i) {
+				u8 *key = (void *)vnic->rss_hash_key;
+				int k;
+
+				bp->toeplitz_prefix = 0;
 				get_random_bytes(vnic->rss_hash_key,
 					      HW_HASH_KEY_SIZE);
-			else
+				for (k = 0; k < 8; k++) {
+					bp->toeplitz_prefix <<= 8;
+					bp->toeplitz_prefix |= key[k];
+				}
+			} else {
 				memcpy(vnic->rss_hash_key,
 				       bp->vnic_info[0].rss_hash_key,
 				       HW_HASH_KEY_SIZE);
+			}
 		}
 	}
 }
@@ -5374,6 +5383,79 @@ static struct bnxt_l2_filter *bnxt_lookup_l2_filter(struct bnxt *bp,
 	return fltr;
 }
 
+#define BNXT_IPV4_4TUPLE(bp, fkeys)					\
+	(((fkeys)->basic.ip_proto == IPPROTO_TCP &&			\
+	  (bp)->rss_hash_cfg & VNIC_RSS_CFG_REQ_HASH_TYPE_TCP_IPV4) ||	\
+	 ((fkeys)->basic.ip_proto == IPPROTO_UDP &&			\
+	  (bp)->rss_hash_cfg & VNIC_RSS_CFG_REQ_HASH_TYPE_UDP_IPV4))
+
+#define BNXT_IPV6_4TUPLE(bp, fkeys)					\
+	(((fkeys)->basic.ip_proto == IPPROTO_TCP &&			\
+	  (bp)->rss_hash_cfg & VNIC_RSS_CFG_REQ_HASH_TYPE_TCP_IPV6) ||	\
+	 ((fkeys)->basic.ip_proto == IPPROTO_UDP &&			\
+	  (bp)->rss_hash_cfg & VNIC_RSS_CFG_REQ_HASH_TYPE_UDP_IPV6))
+
+static u32 bnxt_get_rss_flow_tuple_len(struct bnxt *bp, struct flow_keys *fkeys)
+{
+	if (fkeys->basic.n_proto == htons(ETH_P_IP)) {
+		if (BNXT_IPV4_4TUPLE(bp, fkeys))
+			return sizeof(fkeys->addrs.v4addrs) +
+			       sizeof(fkeys->ports);
+
+		if (bp->rss_hash_cfg & VNIC_RSS_CFG_REQ_HASH_TYPE_IPV4)
+			return sizeof(fkeys->addrs.v4addrs);
+	}
+
+	if (fkeys->basic.n_proto == htons(ETH_P_IPV6)) {
+		if (BNXT_IPV6_4TUPLE(bp, fkeys))
+			return sizeof(fkeys->addrs.v6addrs) +
+			       sizeof(fkeys->ports);
+
+		if (bp->rss_hash_cfg & VNIC_RSS_CFG_REQ_HASH_TYPE_IPV6)
+			return sizeof(fkeys->addrs.v6addrs);
+	}
+
+	return 0;
+}
+
+static u32 bnxt_toeplitz(struct bnxt *bp, struct flow_keys *fkeys,
+			 const unsigned char *key)
+{
+	u64 prefix = bp->toeplitz_prefix, hash = 0;
+	struct bnxt_ipv4_tuple tuple4;
+	struct bnxt_ipv6_tuple tuple6;
+	int i, j, len = 0;
+	u8 *four_tuple;
+
+	len = bnxt_get_rss_flow_tuple_len(bp, fkeys);
+	if (!len)
+		return 0;
+
+	if (fkeys->basic.n_proto == htons(ETH_P_IP)) {
+		tuple4.v4addrs = fkeys->addrs.v4addrs;
+		tuple4.ports = fkeys->ports;
+		four_tuple = (unsigned char *)&tuple4;
+	} else {
+		tuple6.v6addrs = fkeys->addrs.v6addrs;
+		tuple6.ports = fkeys->ports;
+		four_tuple = (unsigned char *)&tuple6;
+	}
+
+	for (i = 0, j = 8; i < len; i++, j++) {
+		u8 byte = four_tuple[i];
+		int bit;
+
+		for (bit = 0; bit < 8; bit++, prefix <<= 1, byte <<= 1) {
+			if (byte & 0x80)
+				hash ^= prefix;
+		}
+		prefix |= (j < HW_HASH_KEY_SIZE) ? key[j] : 0;
+	}
+
+	/* The valid part of the hash is in the upper 32 bits. */
+	return (hash >> 32) & BNXT_NTP_FLTR_HASH_MASK;
+}
+
 #ifdef CONFIG_RFS_ACCEL
 static struct bnxt_l2_filter *
 bnxt_lookup_l2_filter_from_key(struct bnxt *bp, struct bnxt_l2_key *key)
@@ -13774,6 +13856,18 @@ static int bnxt_setup_tc(struct net_device *dev, enum tc_setup_type type,
 	}
 }
 
+static u32 bnxt_get_ntp_filter_idx(struct bnxt *bp, struct flow_keys *fkeys,
+				   const struct sk_buff *skb)
+{
+	struct bnxt_vnic_info *vnic;
+
+	if (skb)
+		return skb_get_hash_raw(skb) & BNXT_NTP_FLTR_HASH_MASK;
+
+	vnic = &bp->vnic_info[0];
+	return bnxt_toeplitz(bp, fkeys, (void *)vnic->rss_hash_key);
+}
+
 #ifdef CONFIG_RFS_ACCEL
 static bool bnxt_fltr_match(struct bnxt_ntuple_filter *f1,
 			    struct bnxt_ntuple_filter *f2)
@@ -13866,7 +13960,7 @@ static int bnxt_rx_flow_steer(struct net_device *dev, const struct sk_buff *skb,
 
 	new_fltr->l2_fltr = l2_fltr;
 
-	idx = skb_get_hash_raw(skb) & BNXT_NTP_FLTR_HASH_MASK;
+	idx = bnxt_get_ntp_filter_idx(bp, fkeys, skb);
 	head = &bp->ntp_fltr_hash_tbl[idx];
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(fltr, head, base.hash) {

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -1370,6 +1370,16 @@ struct bnxt_l2_key {
 	};
 };
 
+struct bnxt_ipv4_tuple {
+	struct flow_dissector_key_ipv4_addrs v4addrs;
+	struct flow_dissector_key_ports ports;
+};
+
+struct bnxt_ipv6_tuple {
+	struct flow_dissector_key_ipv6_addrs v6addrs;
+	struct flow_dissector_key_ports ports;
+};
+
 #define BNXT_L2_KEY_SIZE	(sizeof(struct bnxt_l2_key) / 4)
 
 struct bnxt_l2_filter {
@@ -2413,6 +2423,7 @@ struct bnxt {
 	struct hlist_head	l2_fltr_hash_tbl[BNXT_L2_FLTR_HASH_SIZE];
 
 	u32			hash_seed;
+	u64			toeplitz_prefix;
 
 	/* To protect link related settings during link changes and
 	 * ethtool settings changes.