On 1/28/25 12:46 AM, Jason Xing wrote:
In this patch, we finish the hardware part. Then bpf program can
fetch the hwstamp from skb directly.
To avoid changing so many callers using SKBTX_HW_TSTAMP from drivers,
use this simple modification like this patch does to support printing
hardware timestamp.
Signed-off-by: Jason Xing <kerneljasonxing@xxxxxxxxx>
---
include/linux/skbuff.h | 4 +++-
include/uapi/linux/bpf.h | 7 +++++++
net/core/skbuff.c | 11 ++++++-----
net/dsa/user.c | 2 +-
net/socket.c | 2 +-
tools/include/uapi/linux/bpf.h | 7 +++++++
6 files changed, 25 insertions(+), 8 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index de8d3bd311f5..df2d790ae36b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -471,7 +471,7 @@ struct skb_shared_hwtstamps {
/* Definitions for tx_flags in struct skb_shared_info */
enum {
/* generate hardware time stamp */
- SKBTX_HW_TSTAMP = 1 << 0,
+ __SKBTX_HW_TSTAMP = 1 << 0,
/* generate software time stamp when queueing packet to NIC */
SKBTX_SW_TSTAMP = 1 << 1,
@@ -495,6 +495,8 @@ enum {
SKBTX_BPF = 1 << 7,
};
+#define SKBTX_HW_TSTAMP (__SKBTX_HW_TSTAMP | SKBTX_BPF)
+
#define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
SKBTX_SCHED_TSTAMP | \
SKBTX_BPF)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 6a1083bcf779..4c3566f623c2 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -7040,6 +7040,13 @@ enum {
* to the nic when SK_BPF_CB_TX_TIMESTAMPING
* feature is on.
*/
+ BPF_SOCK_OPS_TS_HW_OPT_CB, /* Called in hardware phase when
+ * SK_BPF_CB_TX_TIMESTAMPING feature
+ * is on. At the same time, hwtstamps
+ * of skb is initialized as the
+ * timestamp that hardware just
+ * generates.
+ */
};
/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 288eb9869827..c769feae5162 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5548,7 +5548,7 @@ static bool skb_enable_app_tstamp(struct sk_buff *skb, int tstype, bool sw)
flag = SKBTX_SCHED_TSTAMP;
break;
case SCM_TSTAMP_SND:
- flag = sw ? SKBTX_SW_TSTAMP : SKBTX_HW_TSTAMP;
+ flag = sw ? SKBTX_SW_TSTAMP : __SKBTX_HW_TSTAMP;
break;
case SCM_TSTAMP_ACK:
if (TCP_SKB_CB(skb)->txstamp_ack)
@@ -5565,7 +5565,8 @@ static bool skb_enable_app_tstamp(struct sk_buff *skb, int tstype, bool sw)
}
static void skb_tstamp_tx_bpf(struct sk_buff *skb, struct sock *sk,
- int tstype, bool sw)
+ int tstype, bool sw,
+ struct skb_shared_hwtstamps *hwtstamps)
{
int op;
@@ -5577,9 +5578,9 @@ static void skb_tstamp_tx_bpf(struct sk_buff *skb, struct sock *sk,
op = BPF_SOCK_OPS_TS_SCHED_OPT_CB;
break;
case SCM_TSTAMP_SND:
+ op = sw ? BPF_SOCK_OPS_TS_SW_OPT_CB : BPF_SOCK_OPS_TS_HW_OPT_CB;
if (!sw)
Patch 5 mentioned hwtstamps could be NULL, so this should be "if (hwtstamps)" here.
- return;
- op = BPF_SOCK_OPS_TS_SW_OPT_CB;
+ *skb_hwtstamps(skb) = *hwtstamps;
Otherwise, this will crash.
pw-bot: cr
break;
default:
return;
