diff mbox series

[net-next,v2,2/3] net: ethernet: ti: am65-cpsw: enable bc/mc storm prevention support

Message ID 20211101170122.19160-3-grygorii.strashko@ti.com (mailing list archive)
State Deferred
Delegated to: Netdev Maintainers
Headers show
Series net: ethernet: ti: cpsw: enable bc/mc storm prevention support | expand

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Commit Message

Grygorii Strashko Nov. 1, 2021, 5:01 p.m. UTC
This patch enables support for ingress broadcast(BC)/multicast(MC) packets
rate limiting in TI AM65x CPSW driver (the corresponding ALE support was
added in previous patch) by implementing HW offload for simple tc-flower
with policer action with matches on dst_mac:
 - ff:ff:ff:ff:ff:ff has to be used for BC packets rate limiting (exact
   match)
 - 01:00:00:00:00:00 fixed value has to be used for MC packets rate
   limiting (exact match)

The CPSW supports MC/BC packets rate limiting in packets/sec and affects
all ingress MC/BC packets and serves as BC/MC storm prevention feature.

Examples:
- BC rate limit to 1000pps:
  tc qdisc add dev eth0 clsact
  tc filter add dev eth0 ingress flower skip_sw dst_mac ff:ff:ff:ff:ff:ff \
  action police pkts_rate 1000 pkts_burst 1

- MC rate limit to 20000pps:
  tc qdisc add dev eth0 clsact
  tc filter add dev eth0 ingress flower skip_sw dst_mac 01:00:00:00:00:00 \
  action police pkts_rate 10000 pkts_burst 1

  pkts_burst - not used.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
 drivers/net/ethernet/ti/am65-cpsw-qos.c | 145 ++++++++++++++++++++++++
 drivers/net/ethernet/ti/am65-cpsw-qos.h |   8 ++
 2 files changed, 153 insertions(+)

Comments

Jakub Kicinski Nov. 3, 2021, 12:38 a.m. UTC | #1
On Mon, 1 Nov 2021 19:01:21 +0200 Grygorii Strashko wrote:
>  - 01:00:00:00:00:00 fixed value has to be used for MC packets rate
>    limiting (exact match)

This looks like a stretch, why not use a mask? You can require users to
always install both BC and MC rules if you want to make sure the masked
rule does not match BC.
Grygorii Strashko Nov. 3, 2021, 10:20 p.m. UTC | #2
hi Jakub,

On 03/11/2021 02:38, Jakub Kicinski wrote:
> On Mon, 1 Nov 2021 19:01:21 +0200 Grygorii Strashko wrote:
>>   - 01:00:00:00:00:00 fixed value has to be used for MC packets rate
>>     limiting (exact match)
> 
> This looks like a stretch, why not use a mask? You can require users to
> always install both BC and MC rules if you want to make sure the masked
> rule does not match BC.
> 

Those matching rules are hard coded in HW for packet rate limiting and SW only
enables them and sets requested pps limit.
- 1:BC: HW does exact match on BC MAC address
- 2:MC: HW does match on MC bit (the least-significant bit of the first octet)

Therefore the exact match done in this patch for above dst_mac's with
is_broadcast_ether_addr() and ether_addr_equal().

The K3 cpsw also supports number configurable policiers (bit rate limit) in
ALE for which supports is to be added, and for them MC mask (sort of, it uses
number of ignored bits, like FF-FF-FF-00-00-00) can be used.
Jakub Kicinski Nov. 3, 2021, 11:07 p.m. UTC | #3
On Thu, 4 Nov 2021 00:20:30 +0200 Grygorii Strashko wrote:
> On 03/11/2021 02:38, Jakub Kicinski wrote:
> > On Mon, 1 Nov 2021 19:01:21 +0200 Grygorii Strashko wrote:  
> >>   - 01:00:00:00:00:00 fixed value has to be used for MC packets rate
> >>     limiting (exact match)  
> > 
> > This looks like a stretch, why not use a mask? You can require users to
> > always install both BC and MC rules if you want to make sure the masked
> > rule does not match BC.
> >   
> 
> Those matching rules are hard coded in HW for packet rate limiting and SW only
> enables them and sets requested pps limit.
> - 1:BC: HW does exact match on BC MAC address
> - 2:MC: HW does match on MC bit (the least-significant bit of the first octet)
> 
> Therefore the exact match done in this patch for above dst_mac's with
> is_broadcast_ether_addr() and ether_addr_equal().

Right but flower supports masked matches for dest address, as far as I
can tell. So you should check the mask is what you expect as well, not
just look at the key. Mask should be equal to key in your case IIUC, so:

	if (is_broadcast_ether_addr(match.key->dst) &&
	    is_broadcast_ether_addr(match.mask->dst))

and

	if (!memcmp(match.key->dst, mc_mac, ETH_ALEN) &&
	    !memcmp(match.mask->dst, mc_mac, ETH_ALEN))

I think you should also test that the mask, not the key of source addr
is zero.

Note that ether_addr_equal() assumes the mac address is alinged to 2,
which I'm not sure is the case here.

Also you can make mc_mac a static const.

> The K3 cpsw also supports number configurable policiers (bit rate limit) in
> ALE for which supports is to be added, and for them MC mask (sort of, it uses
> number of ignored bits, like FF-FF-FF-00-00-00) can be used.
Grygorii Strashko Nov. 3, 2021, 11:19 p.m. UTC | #4
On 04/11/2021 01:07, Jakub Kicinski wrote:
> On Thu, 4 Nov 2021 00:20:30 +0200 Grygorii Strashko wrote:
>> On 03/11/2021 02:38, Jakub Kicinski wrote:
>>> On Mon, 1 Nov 2021 19:01:21 +0200 Grygorii Strashko wrote:
>>>>    - 01:00:00:00:00:00 fixed value has to be used for MC packets rate
>>>>      limiting (exact match)
>>>
>>> This looks like a stretch, why not use a mask? You can require users to
>>> always install both BC and MC rules if you want to make sure the masked
>>> rule does not match BC.
>>>    
>>
>> Those matching rules are hard coded in HW for packet rate limiting and SW only
>> enables them and sets requested pps limit.
>> - 1:BC: HW does exact match on BC MAC address
>> - 2:MC: HW does match on MC bit (the least-significant bit of the first octet)
>>
>> Therefore the exact match done in this patch for above dst_mac's with
>> is_broadcast_ether_addr() and ether_addr_equal().
> 
> Right but flower supports masked matches for dest address, as far as I
> can tell. So you should check the mask is what you expect as well, not
> just look at the key. Mask should be equal to key in your case IIUC, so:
> 
> 	if (is_broadcast_ether_addr(match.key->dst) &&
> 	    is_broadcast_ether_addr(match.mask->dst))
> 
> and
> 
> 	if (!memcmp(match.key->dst, mc_mac, ETH_ALEN) &&
> 	    !memcmp(match.mask->dst, mc_mac, ETH_ALEN))
> 
> I think you should also test that the mask, not the key of source addr
> is zero.
> 
> Note that ether_addr_equal() assumes the mac address is alinged to 2,
> which I'm not sure is the case here.
> 
> Also you can make mc_mac a static const.

Ah, got it. Thank you.

> 
>> The K3 cpsw also supports number configurable policiers (bit rate limit) in
>> ALE for which supports is to be added, and for them MC mask (sort of, it uses
>> number of ignored bits, like FF-FF-FF-00-00-00) can be used.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/ti/am65-cpsw-qos.c b/drivers/net/ethernet/ti/am65-cpsw-qos.c
index ebcc6386cc34..41f0cf56eeb8 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-qos.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-qos.c
@@ -8,10 +8,12 @@ 
 
 #include <linux/pm_runtime.h>
 #include <linux/time.h>
+#include <net/pkt_cls.h>
 
 #include "am65-cpsw-nuss.h"
 #include "am65-cpsw-qos.h"
 #include "am65-cpts.h"
+#include "cpsw_ale.h"
 
 #define AM65_CPSW_REG_CTL			0x004
 #define AM65_CPSW_PN_REG_CTL			0x004
@@ -588,12 +590,155 @@  static int am65_cpsw_setup_taprio(struct net_device *ndev, void *type_data)
 	return am65_cpsw_set_taprio(ndev, type_data);
 }
 
+static int am65_cpsw_qos_clsflower_add_policer(struct am65_cpsw_port *port,
+					       struct netlink_ext_ack *extack,
+					       struct flow_cls_offload *cls,
+					       u64 rate_pkt_ps)
+{
+	struct flow_rule *rule = flow_cls_offload_flow_rule(cls);
+	struct flow_dissector *dissector = rule->match.dissector;
+	u8 mc_mac[] = {0x01, 0x00, 0x00, 0x00, 0x00, 0x00};
+	struct am65_cpsw_qos *qos = &port->qos;
+	struct flow_match_eth_addrs match;
+	int ret;
+
+	if (dissector->used_keys &
+	    ~(BIT(FLOW_DISSECTOR_KEY_BASIC) |
+	      BIT(FLOW_DISSECTOR_KEY_CONTROL) |
+	      BIT(FLOW_DISSECTOR_KEY_ETH_ADDRS))) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Unsupported keys used");
+		return -EOPNOTSUPP;
+	}
+
+	if (!flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
+		NL_SET_ERR_MSG_MOD(extack, "Not matching on eth address");
+		return -EOPNOTSUPP;
+	}
+
+	flow_rule_match_eth_addrs(rule, &match);
+
+	if (!is_zero_ether_addr(match.key->src)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Matching on source MAC not supported");
+		return -EOPNOTSUPP;
+	}
+
+	if (is_broadcast_ether_addr(match.key->dst)) {
+		ret = cpsw_ale_rx_ratelimit_bc(port->common->ale, port->port_id, rate_pkt_ps);
+		if (ret)
+			return ret;
+
+		qos->ale_bc_ratelimit.cookie = cls->cookie;
+		qos->ale_bc_ratelimit.rate_packet_ps = rate_pkt_ps;
+	}
+
+	if (ether_addr_equal(match.key->dst, mc_mac)) {
+		ret = cpsw_ale_rx_ratelimit_mc(port->common->ale, port->port_id, rate_pkt_ps);
+		if (ret)
+			return ret;
+
+		qos->ale_mc_ratelimit.cookie = cls->cookie;
+		qos->ale_mc_ratelimit.rate_packet_ps = rate_pkt_ps;
+	}
+
+	return 0;
+}
+
+static int am65_cpsw_qos_configure_clsflower(struct am65_cpsw_port *port,
+					     struct flow_cls_offload *cls)
+{
+	struct flow_rule *rule = flow_cls_offload_flow_rule(cls);
+	struct netlink_ext_ack *extack = cls->common.extack;
+	const struct flow_action_entry *act;
+	int i;
+
+	flow_action_for_each(i, act, &rule->action) {
+		switch (act->id) {
+		case FLOW_ACTION_POLICE:
+			if (act->police.rate_bytes_ps) {
+				NL_SET_ERR_MSG_MOD(extack,
+						   "QoS offload not support bytes per second");
+				return -EOPNOTSUPP;
+			}
+
+			return am65_cpsw_qos_clsflower_add_policer(port, extack, cls,
+								   act->police.rate_pkt_ps);
+		default:
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Action not supported");
+			return -EOPNOTSUPP;
+		}
+	}
+	return -EOPNOTSUPP;
+}
+
+static int am65_cpsw_qos_delete_clsflower(struct am65_cpsw_port *port, struct flow_cls_offload *cls)
+{
+	struct am65_cpsw_qos *qos = &port->qos;
+
+	if (cls->cookie == qos->ale_bc_ratelimit.cookie) {
+		qos->ale_bc_ratelimit.cookie = 0;
+		qos->ale_bc_ratelimit.rate_packet_ps = 0;
+		cpsw_ale_rx_ratelimit_bc(port->common->ale, port->port_id, 0);
+	}
+
+	if (cls->cookie == qos->ale_mc_ratelimit.cookie) {
+		qos->ale_mc_ratelimit.cookie = 0;
+		qos->ale_mc_ratelimit.rate_packet_ps = 0;
+		cpsw_ale_rx_ratelimit_mc(port->common->ale, port->port_id, 0);
+	}
+
+	return 0;
+}
+
+static int am65_cpsw_qos_setup_tc_clsflower(struct am65_cpsw_port *port,
+					    struct flow_cls_offload *cls_flower)
+{
+	switch (cls_flower->command) {
+	case FLOW_CLS_REPLACE:
+		return am65_cpsw_qos_configure_clsflower(port, cls_flower);
+	case FLOW_CLS_DESTROY:
+		return am65_cpsw_qos_delete_clsflower(port, cls_flower);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int am65_cpsw_qos_setup_tc_block_cb(enum tc_setup_type type, void *type_data, void *cb_priv)
+{
+	struct am65_cpsw_port *port = cb_priv;
+
+	if (!tc_cls_can_offload_and_chain0(port->ndev, type_data))
+		return -EOPNOTSUPP;
+
+	switch (type) {
+	case TC_SETUP_CLSFLOWER:
+		return am65_cpsw_qos_setup_tc_clsflower(port, type_data);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static LIST_HEAD(am65_cpsw_qos_block_cb_list);
+
+static int am65_cpsw_qos_setup_tc_block(struct net_device *ndev, struct flow_block_offload *f)
+{
+	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
+
+	return flow_block_cb_setup_simple(f, &am65_cpsw_qos_block_cb_list,
+					  am65_cpsw_qos_setup_tc_block_cb,
+					  port, port, true);
+}
+
 int am65_cpsw_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
 			       void *type_data)
 {
 	switch (type) {
 	case TC_SETUP_QDISC_TAPRIO:
 		return am65_cpsw_setup_taprio(ndev, type_data);
+	case TC_SETUP_BLOCK:
+		return am65_cpsw_qos_setup_tc_block(ndev, type_data);
 	default:
 		return -EOPNOTSUPP;
 	}
diff --git a/drivers/net/ethernet/ti/am65-cpsw-qos.h b/drivers/net/ethernet/ti/am65-cpsw-qos.h
index e8f1b6b59e93..fb223b43b196 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-qos.h
+++ b/drivers/net/ethernet/ti/am65-cpsw-qos.h
@@ -14,11 +14,19 @@  struct am65_cpsw_est {
 	struct tc_taprio_qopt_offload taprio;
 };
 
+struct am65_cpsw_ale_ratelimit {
+	unsigned long cookie;
+	u64 rate_packet_ps;
+};
+
 struct am65_cpsw_qos {
 	struct am65_cpsw_est *est_admin;
 	struct am65_cpsw_est *est_oper;
 	ktime_t link_down_time;
 	int link_speed;
+
+	struct am65_cpsw_ale_ratelimit ale_bc_ratelimit;
+	struct am65_cpsw_ale_ratelimit ale_mc_ratelimit;
 };
 
 int am65_cpsw_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,