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authorJason Xing <kerneljasonxing@gmail.com>2025-02-20 15:29:37 +0800
committerMartin KaFai Lau <martin.lau@kernel.org>2025-02-20 14:29:43 -0800
commitb3b81e6b009dd8f85cd3b9c65eb492249c2649a8 (patch)
treeab5f6727c4276805bf7dc4b773c2b2636a4e66d0
parent2deaf7f42b8c551e84da20483ca2d4a65c3623b3 (diff)
bpf: Add BPF_SOCK_OPS_TSTAMP_ACK_CB callback
Support the ACK case for bpf timestamping. Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_ACK_CB. This callback will occur at the same timestamping point as the user space's SCM_TSTAMP_ACK. The BPF program can use it to get the same SCM_TSTAMP_ACK timestamp without modifying the user-space application. This patch extends txstamp_ack to two bits: 1 stands for SO_TIMESTAMPING mode, 2 bpf extension. Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250220072940.99994-10-kerneljasonxing@gmail.com
-rw-r--r--include/net/tcp.h6
-rw-r--r--include/uapi/linux/bpf.h5
-rw-r--r--net/core/skbuff.c5
-rw-r--r--net/ipv4/tcp.c2
-rw-r--r--tools/include/uapi/linux/bpf.h5
5 files changed, 19 insertions, 4 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 94ea09faedf4..ae6c95b01012 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -964,10 +964,12 @@ struct tcp_skb_cb {
__u8 sacked; /* State flags for SACK. */
__u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */
- __u8 txstamp_ack:1, /* Record TX timestamp for ack? */
+#define TSTAMP_ACK_SK 0x1
+#define TSTAMP_ACK_BPF 0x2
+ __u8 txstamp_ack:2, /* Record TX timestamp for ack? */
eor:1, /* Is skb MSG_EOR marked? */
has_rxtstamp:1, /* SKB has a RX timestamp */
- unused:5;
+ unused:4;
__u32 ack_seq; /* Sequence number ACK'd */
union {
struct {
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 72045c242396..cc10104f34a0 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -7044,6 +7044,11 @@ enum {
* SK_BPF_CB_TX_TIMESTAMPING feature
* is on.
*/
+ BPF_SOCK_OPS_TSTAMP_ACK_CB, /* Called when all the skbs in the
+ * same sendmsg call are acked
+ * when SK_BPF_CB_TX_TIMESTAMPING
+ * feature is on.
+ */
};
/* 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 77b8866f94c5..dd33c12f00ca 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5550,7 +5550,7 @@ static bool skb_tstamp_tx_report_so_timestamping(struct sk_buff *skb,
return skb_shinfo(skb)->tx_flags & (hwtstamps ? SKBTX_HW_TSTAMP_NOBPF :
SKBTX_SW_TSTAMP);
case SCM_TSTAMP_ACK:
- return TCP_SKB_CB(skb)->txstamp_ack;
+ return TCP_SKB_CB(skb)->txstamp_ack & TSTAMP_ACK_SK;
}
return false;
@@ -5575,6 +5575,9 @@ static void skb_tstamp_tx_report_bpf_timestamping(struct sk_buff *skb,
op = BPF_SOCK_OPS_TSTAMP_SND_SW_CB;
}
break;
+ case SCM_TSTAMP_ACK:
+ op = BPF_SOCK_OPS_TSTAMP_ACK_CB;
+ break;
default:
return;
}
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 992d5c9b2487..2171e2f045bb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -492,7 +492,7 @@ static void tcp_tx_timestamp(struct sock *sk, struct sockcm_cookie *sockc)
sock_tx_timestamp(sk, sockc, &shinfo->tx_flags);
if (tsflags & SOF_TIMESTAMPING_TX_ACK)
- tcb->txstamp_ack = 1;
+ tcb->txstamp_ack |= TSTAMP_ACK_SK;
if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 72045c242396..cc10104f34a0 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -7044,6 +7044,11 @@ enum {
* SK_BPF_CB_TX_TIMESTAMPING feature
* is on.
*/
+ BPF_SOCK_OPS_TSTAMP_ACK_CB, /* Called when all the skbs in the
+ * same sendmsg call are acked
+ * when SK_BPF_CB_TX_TIMESTAMPING
+ * feature is on.
+ */
};
/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect