net: dsa: sja1105: support flow-based redirection via virtual links

Implement tc-flower offloads for redirect, trap and drop using
non-critical virtual links.

Commands which were tested to work are:

  # Send frames received on swp2 with a DA of 42:be:24:9b:76:20 to the
  # CPU and to swp3. This type of key (DA only) when the port's VLAN
  # awareness state is off.
  tc qdisc add dev swp2 clsact
  tc filter add dev swp2 ingress flower skip_sw dst_mac 42:be:24:9b:76:20 \
          action mirred egress redirect dev swp3 \
          action trap

  # Drop frames received on swp2 with a DA of 42:be:24:9b:76:20, a VID
  # of 100 and a PCP of 0.
  tc filter add dev swp2 ingress protocol 802.1Q flower skip_sw \
          dst_mac 42:be:24:9b:76:20 vlan_id 100 vlan_prio 0 action drop

Under the hood, all rules match on DMAC, VID and PCP, but when VLAN
filtering is disabled, those are set internally by the driver to the
port-based defaults. Because we would be put in an awkward situation if
the user were to change the VLAN filtering state while there are active
rules (packets would no longer match on the specified keys), we simply
deny changing vlan_filtering unless the list of flows offloaded via
virtual links is empty. Then the user can re-add new rules.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 302 insertions, 0 deletions

diff --git a/drivers/net/dsa/sja1105/sja1105_vl.c b/drivers/net/dsa/sja1105/sja1105_vl.c
new file mode 100644
index 000000000000..c226779b8275
--- /dev/null
+++ b/drivers/net/dsa/sja1105/sja1105_vl.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright 2020, NXP Semiconductors
+ */
+#include <linux/dsa/8021q.h>
+#include "sja1105.h"
+
+/* The switch flow classification core implements TTEthernet, which 'thinks' in
+ * terms of Virtual Links (VL), a concept borrowed from ARINC 664 part 7.
+ * However it also has one other operating mode (VLLUPFORMAT=0) where it acts
+ * somewhat closer to a pre-standard implementation of IEEE 802.1Qci
+ * (Per-Stream Filtering and Policing), which is what the driver is going to be
+ * implementing.
+ *
+ *                                 VL Lookup
+ *        Key = {DMAC && VLANID   +---------+  Key = { (DMAC[47:16] & VLMASK ==
+ *               && VLAN PCP      |         |                         VLMARKER)
+ *               && INGRESS PORT} +---------+                      (both fixed)
+ *            (exact match,            |             && DMAC[15:0] == VLID
+ *         all specified in rule)      |                    (specified in rule)
+ *                                     v             && INGRESS PORT }
+ *                               ------------
+ *                    0 (PSFP)  /            \  1 (ARINC664)
+ *                 +-----------/  VLLUPFORMAT \----------+
+ *                 |           \    (fixed)   /          |
+ *                 |            \            /           |
+ *  0 (forwarding) v             ------------            |
+ *           ------------                                |
+ *          /            \  1 (QoS classification)       |
+ *     +---/  ISCRITICAL  \-----------+                  |
+ *     |   \  (per rule)  /           |                  |
+ *     |    \            /   VLID taken from      VLID taken from
+ *     v     ------------     index of rule       contents of rule
+ *  select                     that matched         that matched
+ * DESTPORTS                          |                  |
+ *  |                                 +---------+--------+
+ *  |                                           |
+ *  |                                           v
+ *  |                                     VL Forwarding
+ *  |                                   (indexed by VLID)
+ *  |                                      +---------+
+ *  |                       +--------------|         |
+ *  |                       |  select TYPE +---------+
+ *  |                       v
+ *  |   0 (rate      ------------    1 (time
+ *  |  constrained) /            \   triggered)
+ *  |       +------/     TYPE     \------------+
+ *  |       |      \  (per VLID)  /            |
+ *  |       v       \            /             v
+ *  |  VL Policing   ------------         VL Policing
+ *  | (indexed by VLID)                (indexed by VLID)
+ *  |  +---------+                        +---------+
+ *  |  | TYPE=0  |                        | TYPE=1  |
+ *  |  +---------+                        +---------+
+ *  |  select SHARINDX                 select SHARINDX to
+ *  |  to rate-limit                 re-enter VL Forwarding
+ *  |  groups of VL's               with new VLID for egress
+ *  |  to same quota                           |
+ *  |       |                                  |
+ *  |  select MAXLEN -> exceed => drop    select MAXLEN -> exceed => drop
+ *  |       |                                  |
+ *  |       v                                  v
+ *  |  VL Forwarding                      VL Forwarding
+ *  | (indexed by SHARINDX)             (indexed by SHARINDX)
+ *  |  +---------+                        +---------+
+ *  |  | TYPE=0  |                        | TYPE=1  |
+ *  |  +---------+                        +---------+
+ *  |  select PRIORITY,                 select PRIORITY,
+ *  | PARTITION, DESTPORTS            PARTITION, DESTPORTS
+ *  |       |                                  |
+ *  |       v                                  v
+ *  |  VL Policing                        VL Policing
+ *  | (indexed by SHARINDX)           (indexed by SHARINDX)
+ *  |  +---------+                        +---------+
+ *  |  | TYPE=0  |                        | TYPE=1  |
+ *  |  +---------+                        +---------+
+ *  |       |                                  |
+ *  |       v                                  |
+ *  |  select BAG, -> exceed => drop           |
+ *  |    JITTER                                v
+ *  |       |             ----------------------------------------------
+ *  |       |            /    Reception Window is open for this VL      \
+ *  |       |           /    (the Schedule Table executes an entry i     \
+ *  |       |          /   M <= i < N, for which these conditions hold):  \ no
+ *  |       |    +----/                                                    \-+
+ *  |       |    |yes \       WINST[M] == 1 && WINSTINDEX[M] == VLID       / |
+ *  |       |    |     \     WINEND[N] == 1 && WINSTINDEX[N] == VLID      /  |
+ *  |       |    |      \                                                /   |
+ *  |       |    |       \ (the VL window has opened and not yet closed)/    |
+ *  |       |    |        ----------------------------------------------     |
+ *  |       |    v                                                           v
+ *  |       |  dispatch to DESTPORTS when the Schedule Table               drop
+ *  |       |  executes an entry i with TXEN == 1 && VLINDEX == i
+ *  v       v
+ * dispatch immediately to DESTPORTS
+ *
+ * The per-port classification key is always composed of {DMAC, VID, PCP} and
+ * is non-maskable. This 'looks like' the NULL stream identification function
+ * from IEEE 802.1CB clause 6, except for the extra VLAN PCP. When the switch
+ * ports operate as VLAN-unaware, we do allow the user to not specify the VLAN
+ * ID and PCP, and then the port-based defaults will be used.
+ *
+ * In TTEthernet, routing is something that needs to be done manually for each
+ * Virtual Link. So the flow action must always include one of:
+ * a. 'redirect', 'trap' or 'drop': select the egress port list
+ * Additionally, the following actions may be applied on a Virtual Link,
+ * turning it into 'critical' traffic:
+ * b. 'police': turn it into a rate-constrained VL, with bandwidth limitation
+ *    given by the maximum frame length, bandwidth allocation gap (BAG) and
+ *    maximum jitter.
+ * c. 'gate': turn it into a time-triggered VL, which can be only be received
+ *    and forwarded according to a given schedule.
+ */
+
+static bool sja1105_vl_key_lower(struct sja1105_vl_lookup_entry *a,
+				 struct sja1105_vl_lookup_entry *b)
+{
+	if (a->macaddr < b->macaddr)
+		return true;
+	if (a->macaddr > b->macaddr)
+		return false;
+	if (a->vlanid < b->vlanid)
+		return true;
+	if (a->vlanid > b->vlanid)
+		return false;
+	if (a->port < b->port)
+		return true;
+	if (a->port > b->port)
+		return false;
+	if (a->vlanprior < b->vlanprior)
+		return true;
+	if (a->vlanprior > b->vlanprior)
+		return false;
+	/* Keys are equal */
+	return false;
+}
+
+static int sja1105_init_virtual_links(struct sja1105_private *priv,
+				      struct netlink_ext_ack *extack)
+{
+	struct sja1105_vl_lookup_entry *vl_lookup;
+	struct sja1105_table *table;
+	struct sja1105_rule *rule;
+	int num_virtual_links = 0;
+	int i, j, k;
+
+	/* Figure out the dimensioning of the problem */
+	list_for_each_entry(rule, &priv->flow_block.rules, list) {
+		if (rule->type != SJA1105_RULE_VL)
+			continue;
+		/* Each VL lookup entry matches on a single ingress port */
+		num_virtual_links += hweight_long(rule->port_mask);
+	}
+
+	if (num_virtual_links > SJA1105_MAX_VL_LOOKUP_COUNT) {
+		NL_SET_ERR_MSG_MOD(extack, "Not enough VL entries available");
+		return -ENOSPC;
+	}
+
+	/* Discard previous VL Lookup Table */
+	table = &priv->static_config.tables[BLK_IDX_VL_LOOKUP];
+	if (table->entry_count) {
+		kfree(table->entries);
+		table->entry_count = 0;
+	}
+
+	/* Nothing to do */
+	if (!num_virtual_links)
+		return 0;
+
+	/* Pre-allocate space in the static config tables */
+
+	/* VL Lookup Table */
+	table = &priv->static_config.tables[BLK_IDX_VL_LOOKUP];
+	table->entries = kcalloc(num_virtual_links,
+				 table->ops->unpacked_entry_size,
+				 GFP_KERNEL);
+	if (!table->entries)
+		return -ENOMEM;
+	table->entry_count = num_virtual_links;
+	vl_lookup = table->entries;
+
+	k = 0;
+
+	list_for_each_entry(rule, &priv->flow_block.rules, list) {
+		unsigned long port;
+
+		if (rule->type != SJA1105_RULE_VL)
+			continue;
+
+		for_each_set_bit(port, &rule->port_mask, SJA1105_NUM_PORTS) {
+			vl_lookup[k].format = SJA1105_VL_FORMAT_PSFP;
+			vl_lookup[k].port = port;
+			vl_lookup[k].macaddr = rule->key.vl.dmac;
+			if (rule->key.type == SJA1105_KEY_VLAN_AWARE_VL) {
+				vl_lookup[k].vlanid = rule->key.vl.vid;
+				vl_lookup[k].vlanprior = rule->key.vl.pcp;
+			} else {
+				u16 vid = dsa_8021q_rx_vid(priv->ds, port);
+
+				vl_lookup[k].vlanid = vid;
+				vl_lookup[k].vlanprior = 0;
+			}
+			/* For critical VLs, the DESTPORTS mask is taken from
+			 * the VL Forwarding Table, so no point in putting it
+			 * in the VL Lookup Table
+			 */
+			if (rule->vl.type == SJA1105_VL_NONCRITICAL)
+				vl_lookup[k].destports = rule->vl.destports;
+			else
+				vl_lookup[k].iscritical = true;
+			k++;
+		}
+	}
+
+	/* UM10944.pdf chapter 4.2.3 VL Lookup table:
+	 * "the entries in the VL Lookup table must be sorted in ascending
+	 * order (i.e. the smallest value must be loaded first) according to
+	 * the following sort order: MACADDR, VLANID, PORT, VLANPRIOR."
+	 */
+	for (i = 0; i < num_virtual_links; i++) {
+		struct sja1105_vl_lookup_entry *a = &vl_lookup[i];
+
+		for (j = i + 1; j < num_virtual_links; j++) {
+			struct sja1105_vl_lookup_entry *b = &vl_lookup[j];
+
+			if (sja1105_vl_key_lower(b, a)) {
+				struct sja1105_vl_lookup_entry tmp = *a;
+
+				*a = *b;
+				*b = tmp;
+			}
+		}
+	}
+
+	return 0;
+}
+
+int sja1105_vl_redirect(struct sja1105_private *priv, int port,
+			struct netlink_ext_ack *extack, unsigned long cookie,
+			struct sja1105_key *key, unsigned long destports,
+			bool append)
+{
+	struct sja1105_rule *rule = sja1105_rule_find(priv, cookie);
+	int rc;
+
+	if (dsa_port_is_vlan_filtering(dsa_to_port(priv->ds, port)) &&
+	    key->type != SJA1105_KEY_VLAN_AWARE_VL) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Can only redirect based on {DMAC, VID, PCP}");
+		return -EOPNOTSUPP;
+	} else if (key->type != SJA1105_KEY_VLAN_UNAWARE_VL) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Can only redirect based on DMAC");
+		return -EOPNOTSUPP;
+	}
+
+	if (!rule) {
+		rule = kzalloc(sizeof(*rule), GFP_KERNEL);
+		if (!rule)
+			return -ENOMEM;
+
+		rule->cookie = cookie;
+		rule->type = SJA1105_RULE_VL;
+		rule->key = *key;
+		list_add(&rule->list, &priv->flow_block.rules);
+	}
+
+	rule->port_mask |= BIT(port);
+	if (append)
+		rule->vl.destports |= destports;
+	else
+		rule->vl.destports = destports;
+
+	rc = sja1105_init_virtual_links(priv, extack);
+	if (rc) {
+		rule->port_mask &= ~BIT(port);
+		if (!rule->port_mask) {
+			list_del(&rule->list);
+			kfree(rule);
+		}
+	}
+
+	return rc;
+}
+
+int sja1105_vl_delete(struct sja1105_private *priv, int port,
+		      struct sja1105_rule *rule, struct netlink_ext_ack *extack)
+{
+	int rc;
+
+	rule->port_mask &= ~BIT(port);
+	if (!rule->port_mask) {
+		list_del(&rule->list);
+		kfree(rule);
+	}
+
+	rc = sja1105_init_virtual_links(priv, extack);
+	if (rc)
+		return rc;
+
+	return sja1105_static_config_reload(priv, SJA1105_VIRTUAL_LINKS);
+}