diff mbox series

[RESEND,net-next,v4,3/4] sfc: support unicast PTP

Message ID 20230314100925.12040-4-ihuguet@redhat.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series sfc: support unicast PTP | expand

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Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 18 this patch: 18
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 18 this patch: 18
netdev/checkpatch warning WARNING: Reported-by: should be immediately followed by Link: with a URL to the report WARNING: line length of 88 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Íñigo Huguet March 14, 2023, 10:09 a.m. UTC 
When sending a PTP event packet, add the correct filters that will make
that future incoming unicast PTP event packets will be timestamped.
The unicast address for the filter is gotten from the outgoing skb
before sending it.

Until now they were not timestamped because only filters that match with
the PTP multicast addressed were being configured into the NIC for the
PTP special channel. Packets received through different channels are not
timestamped, getting "received SYNC without timestamp" error in ptp4l.

Note that the inserted filters are never removed unless the NIC is stopped
or reconfigured, so efx_ptp_stop is called. Removal of old filters will
be handled by the next patch.

Additionally, cleanup a bit efx_ptp_xmit_skb_mc to use the reverse xmas
tree convention and remove an unnecessary assignment to rc variable in
void function.

Reported-by: Yalin Li <yalli@redhat.com>
Signed-off-by: Íñigo Huguet <ihuguet@redhat.com>
---
 drivers/net/ethernet/sfc/ptp.c | 108 ++++++++++++++++++++++++++++++++-
 1 file changed, 105 insertions(+), 3 deletions(-)

--
2.34.3

Comments

Edward Cree March 14, 2023, 4:55 p.m. UTC | #1 
On 14/03/2023 10:09, Íñigo Huguet wrote:
> When sending a PTP event packet, add the correct filters that will make
> that future incoming unicast PTP event packets will be timestamped.
> The unicast address for the filter is gotten from the outgoing skb
> before sending it.
> 
> Until now they were not timestamped because only filters that match with
> the PTP multicast addressed were being configured into the NIC for the
> PTP special channel. Packets received through different channels are not
> timestamped, getting "received SYNC without timestamp" error in ptp4l.
> 
> Note that the inserted filters are never removed unless the NIC is stopped
> or reconfigured, so efx_ptp_stop is called. Removal of old filters will
> be handled by the next patch.
> 
> Additionally, cleanup a bit efx_ptp_xmit_skb_mc to use the reverse xmas
> tree convention and remove an unnecessary assignment to rc variable in
> void function.
> 
> Reported-by: Yalin Li <yalli@redhat.com>
> Signed-off-by: Íñigo Huguet <ihuguet@redhat.com>

Few nits below, but still
Acked-by: Edward Cree <ecree.xilinx@gmail.com>

> +static bool efx_ptp_filter_exists(struct list_head *ptp_list,
> +				  struct efx_filter_spec *spec)
> +{
> +	struct efx_ptp_rxfilter *rxfilter;
> +
> +	list_for_each_entry(rxfilter, ptp_list, list) {
> +		if (rxfilter->ether_type == spec->ether_type &&
> +		    rxfilter->loc_port == spec->loc_port &&
> +		    !memcmp(rxfilter->loc_host, spec->loc_host, sizeof(spec->loc_host)))
> +			return true;
> +	}
> +
> +	return false;
> +}

Technically this could be more efficient if we used an rhashtable
 instead of a list, but I guess we don't expect the list to grow
 very long.

> +static int efx_ptp_insert_unicast_filter(struct efx_nic *efx,
> +					 struct sk_buff *skb)
> +{
> +	struct efx_ptp_data *ptp = efx->ptp_data;
> +	int rc;
> +
> +	if (!efx_ptp_valid_unicast_event_pkt(skb))
> +		return -EINVAL;
> +
> +	if (skb->protocol == htons(ETH_P_IP)) {
> +		__be32 addr = ip_hdr(skb)->saddr;
> +
> +		rc = efx_ptp_insert_ipv4_filter(efx, &ptp->rxfilters_ucast,
> +						addr, PTP_EVENT_PORT);
> +		if (rc < 0)
> +			goto fail;
> +
> +		rc = efx_ptp_insert_ipv4_filter(efx, &ptp->rxfilters_ucast,
> +						addr, PTP_GENERAL_PORT);
> +		if (rc < 0)
> +			goto fail;
> +	} else if (efx_ptp_use_mac_tx_timestamps(efx)) {
> +		/* IPv6 PTP only supported by devices with MAC hw timestamp */
> +		struct in6_addr *addr = &ipv6_hdr(skb)->saddr;
> +
> +		rc = efx_ptp_insert_ipv6_filter(efx, &ptp->rxfilters_ucast,
> +						addr, PTP_EVENT_PORT);
> +		if (rc < 0)
> +			goto fail;
> +
> +		rc = efx_ptp_insert_ipv6_filter(efx, &ptp->rxfilters_ucast,
> +						addr, PTP_GENERAL_PORT);
> +		if (rc < 0)
> +			goto fail;
> +	} else {
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return 0;
> +
> +fail:
> +	efx_ptp_remove_filters(efx, &ptp->rxfilters_ucast);
> +	return rc;
> +}

Why does failing to insert one filter mean we need to remove *all*
 the unicast filters we have?  (I'm not even sure it's necessary
 to remove the new EVENT filter if the GENERAL filter fails.)
Íñigo Huguet March 15, 2023, 8:48 a.m. UTC | #2 
El 14/3/23 a las 17:55, Edward Cree escribió:
> On 14/03/2023 10:09, Íñigo Huguet wrote:
>> When sending a PTP event packet, add the correct filters that will make
>> that future incoming unicast PTP event packets will be timestamped.
>> The unicast address for the filter is gotten from the outgoing skb
>> before sending it.
>>
>> Until now they were not timestamped because only filters that match with
>> the PTP multicast addressed were being configured into the NIC for the
>> PTP special channel. Packets received through different channels are not
>> timestamped, getting "received SYNC without timestamp" error in ptp4l.
>>
>> Note that the inserted filters are never removed unless the NIC is stopped
>> or reconfigured, so efx_ptp_stop is called. Removal of old filters will
>> be handled by the next patch.
>>
>> Additionally, cleanup a bit efx_ptp_xmit_skb_mc to use the reverse xmas
>> tree convention and remove an unnecessary assignment to rc variable in
>> void function.
>>
>> Reported-by: Yalin Li <yalli@redhat.com>
>> Signed-off-by: Íñigo Huguet <ihuguet@redhat.com>
> 
> Few nits below, but still
> Acked-by: Edward Cree <ecree.xilinx@gmail.com>
> 
>> +static bool efx_ptp_filter_exists(struct list_head *ptp_list,
>> +				  struct efx_filter_spec *spec)
>> +{
>> +	struct efx_ptp_rxfilter *rxfilter;
>> +
>> +	list_for_each_entry(rxfilter, ptp_list, list) {
>> +		if (rxfilter->ether_type == spec->ether_type &&
>> +		    rxfilter->loc_port == spec->loc_port &&
>> +		    !memcmp(rxfilter->loc_host, spec->loc_host, sizeof(spec->loc_host)))
>> +			return true;
>> +	}
>> +
>> +	return false;
>> +}
> 
> Technically this could be more efficient if we used an rhashtable
>  instead of a list, but I guess we don't expect the list to grow
>  very long.

Yes, I expect the list to be short, so I thought better not to optimize prematurely. However, after giving to it a second thought, maybe the list can grow more if the NIC is acting as unicast PTP master? I mainly considered the slave case...

I've never used rhashlist, it would be a good learning exercise. How do you see if I submit that as an optimization in a future patch?
 
>> +static int efx_ptp_insert_unicast_filter(struct efx_nic *efx,
>> +					 struct sk_buff *skb)
>> +{
>> +	struct efx_ptp_data *ptp = efx->ptp_data;
>> +	int rc;
>> +
>> +	if (!efx_ptp_valid_unicast_event_pkt(skb))
>> +		return -EINVAL;
>> +
>> +	if (skb->protocol == htons(ETH_P_IP)) {
>> +		__be32 addr = ip_hdr(skb)->saddr;
>> +
>> +		rc = efx_ptp_insert_ipv4_filter(efx, &ptp->rxfilters_ucast,
>> +						addr, PTP_EVENT_PORT);
>> +		if (rc < 0)
>> +			goto fail;
>> +
>> +		rc = efx_ptp_insert_ipv4_filter(efx, &ptp->rxfilters_ucast,
>> +						addr, PTP_GENERAL_PORT);
>> +		if (rc < 0)
>> +			goto fail;
>> +	} else if (efx_ptp_use_mac_tx_timestamps(efx)) {
>> +		/* IPv6 PTP only supported by devices with MAC hw timestamp */
>> +		struct in6_addr *addr = &ipv6_hdr(skb)->saddr;
>> +
>> +		rc = efx_ptp_insert_ipv6_filter(efx, &ptp->rxfilters_ucast,
>> +						addr, PTP_EVENT_PORT);
>> +		if (rc < 0)
>> +			goto fail;
>> +
>> +		rc = efx_ptp_insert_ipv6_filter(efx, &ptp->rxfilters_ucast,
>> +						addr, PTP_GENERAL_PORT);
>> +		if (rc < 0)
>> +			goto fail;
>> +	} else {
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	return 0;
>> +
>> +fail:
>> +	efx_ptp_remove_filters(efx, &ptp->rxfilters_ucast);
>> +	return rc;
>> +}
> 
> Why does failing to insert one filter mean we need to remove *all*
>  the unicast filters we have?  (I'm not even sure it's necessary
>  to remove the new EVENT filter if the GENERAL filter fails.)

Well, my reasoning was that it shouldn't fail in a first place. If it does, it's something very weird. Instead of implementing more complex logic to try checking if the current state is valid or not, just remove all and try to install them again the next time. If it fails again, probably the system is not in a very good state.
Edward Cree March 15, 2023, 4:14 p.m. UTC | #3 
On 15/03/2023 08:48, Íñigo Huguet wrote:
> I've never used rhashlist, it would be a good learning exercise. How do you see if I submit that as an optimization in a future patch?

Yep, that'd be fine.  (Hence the Ack.)

>> Why does failing to insert one filter mean we need to remove *all*
>>  the unicast filters we have?  (I'm not even sure it's necessary
>>  to remove the new EVENT filter if the GENERAL filter fails.)
> 
> Well, my reasoning was that it shouldn't fail in a first place. If it does, it's something very weird. Instead of implementing more complex logic to try checking if the current state is valid or not, just remove all and try to install them again the next time. If it fails again, probably the system is not in a very good state.

I don't think any complex logic is needed - any insertion that fails
 will mean that there's no corresponding entry on the list, so next
 time we call efx_ptp_filter_exists() it'll return false and we'll
 go ahead and insert.  I.e. every state is 'valid' as long as the
 rxfilters_ucast list matches what's actually in the hardware.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index 478dd5c06b22..16686aa5bfb4 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -215,10 +215,16 @@  struct efx_ptp_timeset {
 /**
  * struct efx_ptp_rxfilter - Filter for PTP packets
  * @list: Node of the list where the filter is added
+ * @ether_type: Network protocol of the filter (ETHER_P_IP / ETHER_P_IPV6)
+ * @loc_port: UDP port of the filter (PTP_EVENT_PORT / PTP_GENERAL_PORT)
+ * @loc_host: IPv4/v6 address of the filter
  * @handle: Handle ID for the MCDI filters table
  */
 struct efx_ptp_rxfilter {
 	struct list_head list;
+	__be16 ether_type;
+	__be16 loc_port;
+	__be32 loc_host[4];
 	int handle;
 };

@@ -367,6 +373,8 @@  static int efx_phc_settime(struct ptp_clock_info *ptp,
 			   const struct timespec64 *e_ts);
 static int efx_phc_enable(struct ptp_clock_info *ptp,
 			  struct ptp_clock_request *request, int on);
+static int efx_ptp_insert_unicast_filter(struct efx_nic *efx,
+					 struct sk_buff *skb);

 bool efx_ptp_use_mac_tx_timestamps(struct efx_nic *efx)
 {
@@ -1112,6 +1120,8 @@  static void efx_ptp_xmit_skb_queue(struct efx_nic *efx, struct sk_buff *skb)

 	tx_queue = efx_channel_get_tx_queue(ptp_data->channel, type);
 	if (tx_queue && tx_queue->timestamping) {
+		skb_get(skb);
+
 		/* This code invokes normal driver TX code which is always
 		 * protected from softirqs when called from generic TX code,
 		 * which in turn disables preemption. Look at __dev_queue_xmit
@@ -1135,6 +1145,13 @@  static void efx_ptp_xmit_skb_queue(struct efx_nic *efx, struct sk_buff *skb)
 		local_bh_disable();
 		efx_enqueue_skb(tx_queue, skb);
 		local_bh_enable();
+
+		/* We need to add the filters after enqueuing the packet.
+		 * Otherwise, there's high latency in sending back the
+		 * timestamp, causing ptp4l timeouts
+		 */
+		efx_ptp_insert_unicast_filter(efx, skb);
+		dev_consume_skb_any(skb);
 	} else {
 		WARN_ONCE(1, "PTP channel has no timestamped tx queue\n");
 		dev_kfree_skb_any(skb);
@@ -1144,11 +1161,11 @@  static void efx_ptp_xmit_skb_queue(struct efx_nic *efx, struct sk_buff *skb)
 /* Transmit a PTP packet, via the MCDI interface, to the wire. */
 static void efx_ptp_xmit_skb_mc(struct efx_nic *efx, struct sk_buff *skb)
 {
+	MCDI_DECLARE_BUF(txtime, MC_CMD_PTP_OUT_TRANSMIT_LEN);
 	struct efx_ptp_data *ptp_data = efx->ptp_data;
 	struct skb_shared_hwtstamps timestamps;
-	int rc = -EIO;
-	MCDI_DECLARE_BUF(txtime, MC_CMD_PTP_OUT_TRANSMIT_LEN);
 	size_t len;
+	int rc;

 	MCDI_SET_DWORD(ptp_data->txbuf, PTP_IN_OP, MC_CMD_PTP_OP_TRANSMIT);
 	MCDI_SET_DWORD(ptp_data->txbuf, PTP_IN_PERIPH_ID, 0);
@@ -1182,7 +1199,10 @@  static void efx_ptp_xmit_skb_mc(struct efx_nic *efx, struct sk_buff *skb)

 	skb_tstamp_tx(skb, &timestamps);

-	rc = 0;
+	/* Add the filters after sending back the timestamp to avoid delaying it
+	 * or ptp4l may timeout.
+	 */
+	efx_ptp_insert_unicast_filter(efx, skb);

 fail:
 	dev_kfree_skb_any(skb);
@@ -1298,6 +1318,21 @@  static inline void efx_ptp_process_rx(struct efx_nic *efx, struct sk_buff *skb)
 	local_bh_enable();
 }

+static bool efx_ptp_filter_exists(struct list_head *ptp_list,
+				  struct efx_filter_spec *spec)
+{
+	struct efx_ptp_rxfilter *rxfilter;
+
+	list_for_each_entry(rxfilter, ptp_list, list) {
+		if (rxfilter->ether_type == spec->ether_type &&
+		    rxfilter->loc_port == spec->loc_port &&
+		    !memcmp(rxfilter->loc_host, spec->loc_host, sizeof(spec->loc_host)))
+			return true;
+	}
+
+	return false;
+}
+
 static void efx_ptp_remove_filters(struct efx_nic *efx,
 				   struct list_head *ptp_list)
 {
@@ -1328,6 +1363,9 @@  static int efx_ptp_insert_filter(struct efx_nic *efx,
 	struct efx_ptp_rxfilter *rxfilter;
 	int rc;

+	if (efx_ptp_filter_exists(ptp_list, spec))
+		return 0;
+
 	rxfilter = kzalloc(sizeof(*rxfilter), GFP_KERNEL);
 	if (!rxfilter)
 		return -ENOMEM;
@@ -1337,6 +1375,9 @@  static int efx_ptp_insert_filter(struct efx_nic *efx,
 		goto fail;

 	rxfilter->handle = rc;
+	rxfilter->ether_type = spec->ether_type;
+	rxfilter->loc_port = spec->loc_port;
+	memcpy(rxfilter->loc_host, spec->loc_host, sizeof(spec->loc_host));
 	list_add(&rxfilter->list, ptp_list);

 	return 0;
@@ -1429,6 +1470,67 @@  static int efx_ptp_insert_multicast_filters(struct efx_nic *efx)
 	return rc;
 }

+static bool efx_ptp_valid_unicast_event_pkt(struct sk_buff *skb)
+{
+	if (skb->protocol == htons(ETH_P_IP)) {
+		return ip_hdr(skb)->daddr != htonl(PTP_ADDR_IPV4) &&
+			ip_hdr(skb)->protocol == IPPROTO_UDP &&
+			udp_hdr(skb)->source == htons(PTP_EVENT_PORT);
+	} else if (skb->protocol == htons(ETH_P_IPV6)) {
+		struct in6_addr mcast_addr = {{PTP_ADDR_IPV6}};
+
+		return !ipv6_addr_equal(&ipv6_hdr(skb)->daddr, &mcast_addr) &&
+			ipv6_hdr(skb)->nexthdr == IPPROTO_UDP &&
+			udp_hdr(skb)->source == htons(PTP_EVENT_PORT);
+	}
+	return false;
+}
+
+static int efx_ptp_insert_unicast_filter(struct efx_nic *efx,
+					 struct sk_buff *skb)
+{
+	struct efx_ptp_data *ptp = efx->ptp_data;
+	int rc;
+
+	if (!efx_ptp_valid_unicast_event_pkt(skb))
+		return -EINVAL;
+
+	if (skb->protocol == htons(ETH_P_IP)) {
+		__be32 addr = ip_hdr(skb)->saddr;
+
+		rc = efx_ptp_insert_ipv4_filter(efx, &ptp->rxfilters_ucast,
+						addr, PTP_EVENT_PORT);
+		if (rc < 0)
+			goto fail;
+
+		rc = efx_ptp_insert_ipv4_filter(efx, &ptp->rxfilters_ucast,
+						addr, PTP_GENERAL_PORT);
+		if (rc < 0)
+			goto fail;
+	} else if (efx_ptp_use_mac_tx_timestamps(efx)) {
+		/* IPv6 PTP only supported by devices with MAC hw timestamp */
+		struct in6_addr *addr = &ipv6_hdr(skb)->saddr;
+
+		rc = efx_ptp_insert_ipv6_filter(efx, &ptp->rxfilters_ucast,
+						addr, PTP_EVENT_PORT);
+		if (rc < 0)
+			goto fail;
+
+		rc = efx_ptp_insert_ipv6_filter(efx, &ptp->rxfilters_ucast,
+						addr, PTP_GENERAL_PORT);
+		if (rc < 0)
+			goto fail;
+	} else {
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+
+fail:
+	efx_ptp_remove_filters(efx, &ptp->rxfilters_ucast);
+	return rc;
+}
+
 static int efx_ptp_start(struct efx_nic *efx)
 {
 	struct efx_ptp_data *ptp = efx->ptp_data;