[PATCH bpf-next v9 09/12] bpf: support SCM_TSTAMP_ACK of SO_TIMESTAMPING

[Jason Xing <kerneljasonxing@gmail.com>]

Support the ACK timestamp case. Extend txstamp_ack to two bits:
1 stands for SO_TIMESTAMPING mode, 2 bpf extension. The latter
will be used later.

Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
---
 include/net/tcp.h              | 4 ++--
 include/uapi/linux/bpf.h       | 5 +++++
 net/core/skbuff.c              | 5 ++++-
 tools/include/uapi/linux/bpf.h | 5 +++++
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 4c4dca59352b..ef30f3605e04 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -958,10 +958,10 @@ 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? */
+	__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 e71a9b53e7bc..c04e788125a7 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_TS_ACK_OPT_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 ca1ba4252ca5..c0f4d6f6583d 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5549,7 +5549,7 @@ static bool skb_tstamp_tx_report_so_timestamping(struct sk_buff *skb,
 		return skb_shinfo(skb)->tx_flags & (sw ? SKBTX_SW_TSTAMP :
 						    SKBTX_HW_TSTAMP_NOBPF);
 	case SCM_TSTAMP_ACK:
-		return TCP_SKB_CB(skb)->txstamp_ack;
+		return TCP_SKB_CB(skb)->txstamp_ack == 1;
 	}
 
 	return false;
@@ -5569,6 +5569,9 @@ static void skb_tstamp_tx_report_bpf_timestamping(struct sk_buff *skb,
 	case SCM_TSTAMP_SND:
 		op = sw ? BPF_SOCK_OPS_TS_SW_OPT_CB : BPF_SOCK_OPS_TS_HW_OPT_CB;
 		break;
+	case SCM_TSTAMP_ACK:
+		op = BPF_SOCK_OPS_TS_ACK_OPT_CB;
+		break;
 	default:
 		return;
 	}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 7b9652ce7e3c..d3e2988b3b4c 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -7037,6 +7037,11 @@ enum {
 					 * SK_BPF_CB_TX_TIMESTAMPING feature
 					 * is on.
 					 */
+	BPF_SOCK_OPS_TS_ACK_OPT_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
-- 
2.43.5