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Message-Id: <20220403175544.26556-5-gerhard@engleder-embedded.com>
Date: Sun, 3 Apr 2022 19:55:43 +0200
From: Gerhard Engleder <gerhard@...leder-embedded.com>
To: richardcochran@...il.com, vinicius.gomes@...el.com,
yangbo.lu@....com, davem@...emloft.net, kuba@...nel.org
Cc: mlichvar@...hat.com, netdev@...r.kernel.org,
Gerhard Engleder <gerhard@...leder-embedded.com>
Subject: [PATCH net-next v2 4/5] ptp: Support late timestamp determination
If a physical clock supports a free running cycle counter, then
timestamps shall be based on this time too. For TX it is known in
advance before the transmission if a timestamp based on the free running
cycle counter is needed. For RX it is impossible to know which timestamp
is needed before the packet is received and assigned to a socket.
Support late timestamp determination by a network device. Therefore, an
address/cookie is stored within the new netdev_data field of struct
skb_shared_hwtstamps. This address/cookie is provided to a new network
device function called ndo_get_tstamp(), which returns a timestamp based
on the normal/adjustable time or based on the free running cycle
counter. If function is not supported, then timestamp handling is not
changed.
Signed-off-by: Gerhard Engleder <gerhard@...leder-embedded.com>
---
include/linux/netdevice.h | 21 +++++++++++++++++++++
include/linux/skbuff.h | 11 ++++++++---
net/socket.c | 30 +++++++++++++++++++-----------
3 files changed, 48 insertions(+), 14 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 59e27a2b7bf0..f6cc4c673082 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1353,6 +1353,12 @@ struct netdev_net_notifier {
* The caller must be under RCU read context.
* int (*ndo_fill_forward_path)(struct net_device_path_ctx *ctx, struct net_device_path *path);
* Get the forwarding path to reach the real device from the HW destination address
+ * ktime_t (*ndo_get_tstamp)(struct net_device *dev,
+ * const struct skb_shared_hwtstamps *hwtstamps,
+ * bool cycles);
+ * Get hardware timestamp based on normal/adjustable time or free running
+ * cycle counter. This function is required if physical clock supports a
+ * free running cycle counter.
*/
struct net_device_ops {
int (*ndo_init)(struct net_device *dev);
@@ -1570,6 +1576,9 @@ struct net_device_ops {
struct net_device * (*ndo_get_peer_dev)(struct net_device *dev);
int (*ndo_fill_forward_path)(struct net_device_path_ctx *ctx,
struct net_device_path *path);
+ ktime_t (*ndo_get_tstamp)(struct net_device *dev,
+ const struct skb_shared_hwtstamps *hwtstamps,
+ bool cycles);
};
/**
@@ -4764,6 +4773,18 @@ static inline void netdev_rx_csum_fault(struct net_device *dev,
void net_enable_timestamp(void);
void net_disable_timestamp(void);
+static inline ktime_t netdev_get_tstamp(struct net_device *dev,
+ const struct skb_shared_hwtstamps *hwtstamps,
+ bool cycles)
+{
+ const struct net_device_ops *ops = dev->netdev_ops;
+
+ if (ops->ndo_get_tstamp)
+ return ops->ndo_get_tstamp(dev, hwtstamps, cycles);
+
+ return hwtstamps->hwtstamp;
+}
+
#ifdef CONFIG_PROC_FS
int __init dev_proc_init(void);
#else
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index aeb3ed4d6cf8..c428b678e7f1 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -551,8 +551,10 @@ static inline bool skb_frag_must_loop(struct page *p)
/**
* struct skb_shared_hwtstamps - hardware time stamps
- * @hwtstamp: hardware time stamp transformed into duration
- * since arbitrary point in time
+ * @hwtstamp: hardware time stamp transformed into duration
+ * since arbitrary point in time
+ * @netdev_data: address/cookie of network device driver used as
+ * reference to actual hardware time stamp
*
* Software time stamps generated by ktime_get_real() are stored in
* skb->tstamp.
@@ -564,7 +566,10 @@ static inline bool skb_frag_must_loop(struct page *p)
* &skb_shared_info. Use skb_hwtstamps() to get a pointer.
*/
struct skb_shared_hwtstamps {
- ktime_t hwtstamp;
+ union {
+ ktime_t hwtstamp;
+ void *netdev_data;
+ };
};
/* Definitions for tx_flags in struct skb_shared_info */
diff --git a/net/socket.c b/net/socket.c
index 4801aeaeb285..d64bd3dfcf6a 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -805,21 +805,17 @@ static bool skb_is_swtx_tstamp(const struct sk_buff *skb, int false_tstamp)
return skb->tstamp && !false_tstamp && skb_is_err_queue(skb);
}
-static void put_ts_pktinfo(struct msghdr *msg, struct sk_buff *skb)
+static void put_ts_pktinfo(struct msghdr *msg, struct sk_buff *skb,
+ int if_index)
{
struct scm_ts_pktinfo ts_pktinfo;
- struct net_device *orig_dev;
if (!skb_mac_header_was_set(skb))
return;
memset(&ts_pktinfo, 0, sizeof(ts_pktinfo));
- rcu_read_lock();
- orig_dev = dev_get_by_napi_id(skb_napi_id(skb));
- if (orig_dev)
- ts_pktinfo.if_index = orig_dev->ifindex;
- rcu_read_unlock();
+ ts_pktinfo.if_index = if_index;
ts_pktinfo.pkt_length = skb->len - skb_mac_offset(skb);
put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_PKTINFO,
@@ -839,6 +835,8 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
int empty = 1, false_tstamp = 0;
struct skb_shared_hwtstamps *shhwtstamps =
skb_hwtstamps(skb);
+ struct net_device *orig_dev;
+ int if_index;
ktime_t hwtstamp;
/* Race occurred between timestamp enabling and packet
@@ -887,18 +885,28 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
if (shhwtstamps &&
(sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
!skb_is_swtx_tstamp(skb, false_tstamp)) {
+ rcu_read_lock();
+ orig_dev = dev_get_by_napi_id(skb_napi_id(skb));
+ if (orig_dev) {
+ if_index = orig_dev->ifindex;
+ hwtstamp = netdev_get_tstamp(orig_dev, shhwtstamps,
+ sk->sk_tsflags & SOF_TIMESTAMPING_BIND_PHC);
+ } else {
+ if_index = 0;
+ hwtstamp = shhwtstamps->hwtstamp;
+ }
+ rcu_read_unlock();
+
if (sk->sk_tsflags & SOF_TIMESTAMPING_BIND_PHC)
- hwtstamp = ptp_convert_timestamp(&shhwtstamps->hwtstamp,
+ hwtstamp = ptp_convert_timestamp(&hwtstamp,
sk->sk_bind_phc);
- else
- hwtstamp = shhwtstamps->hwtstamp;
if (ktime_to_timespec64_cond(hwtstamp, tss.ts + 2)) {
empty = 0;
if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_PKTINFO) &&
!skb_is_err_queue(skb))
- put_ts_pktinfo(msg, skb);
+ put_ts_pktinfo(msg, skb, if_index);
}
}
if (!empty) {
--
2.20.1
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