A BPF application, e.g., a TCP congestion control, might benefit from or
even require precise (=hardware) packet timestamps. These timestamps are
already available in __sk_buff.hwtstamp and bpf_sock_ops.skb_hwtstamp,
but could not be requested: A BPF program was not allowed to set
SO_TIMESTAMPING* on a socket.
Enable BPF programs to actively request the generation of timestamps
from a stream socket. The also required ioctl(SIOCSHWTSTAMP) on the
network device must still be done separately, in user space.
Signed-off-by: Jörn-Thorben Hinz <jthinz@xxxxxxxxxxxxxxxxxxxx>
---
include/uapi/linux/bpf.h | 3 ++-
net/core/filter.c | 2 ++
tools/include/uapi/linux/bpf.h | 3 ++-
tools/testing/selftests/bpf/progs/bpf_tracing_net.h | 2 ++
tools/testing/selftests/bpf/progs/setget_sockopt.c | 4 ++++
5 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 60a9d59beeab..3e64b8137931 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2640,7 +2640,8 @@ union bpf_attr {
* **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
* **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
* **SO_BINDTODEVICE**, **SO_KEEPALIVE**, **SO_REUSEADDR**,
- * **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**.
+ * **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**,
+ * **SO_TIMESTAMPING_NEW**, **SO_TIMESTAMPING_OLD**.
* * **IPPROTO_TCP**, which supports the following *optname*\ s:
* **TCP_CONGESTION**, **TCP_BPF_IW**,
* **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
diff --git a/net/core/filter.c b/net/core/filter.c
index 06ba0e56e369..af0f3a6762de 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5108,6 +5108,8 @@ static int sol_socket_sockopt(struct sock *sk, int optname,
case SO_MAX_PACING_RATE:
case SO_BINDTOIFINDEX:
case SO_TXREHASH:
+ case SO_TIMESTAMPING_NEW:
+ case SO_TIMESTAMPING_OLD:
if (*optlen != sizeof(int))
return -EINVAL;
break;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 60a9d59beeab..3e64b8137931 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2640,7 +2640,8 @@ union bpf_attr {
* **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
* **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
* **SO_BINDTODEVICE**, **SO_KEEPALIVE**, **SO_REUSEADDR**,
- * **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**.
+ * **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**,
+ * **SO_TIMESTAMPING_NEW**, **SO_TIMESTAMPING_OLD**.
* * **IPPROTO_TCP**, which supports the following *optname*\ s:
* **TCP_CONGESTION**, **TCP_BPF_IW**,
* **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
diff --git a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
index cfed4df490f3..8d526db8ceeb 100644
--- a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
+++ b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h
@@ -15,8 +15,10 @@
#define SO_RCVLOWAT 18
#define SO_BINDTODEVICE 25
#define SO_MARK 36
+#define SO_TIMESTAMPING_OLD 37
#define SO_MAX_PACING_RATE 47
#define SO_BINDTOIFINDEX 62
+#define SO_TIMESTAMPING_NEW 65
#define SO_TXREHASH 74
#define __SO_ACCEPTCON (1 << 16)
diff --git a/tools/testing/selftests/bpf/progs/setget_sockopt.c b/tools/testing/selftests/bpf/progs/setget_sockopt.c
index 7a438600ae98..54205d10793c 100644
--- a/tools/testing/selftests/bpf/progs/setget_sockopt.c
+++ b/tools/testing/selftests/bpf/progs/setget_sockopt.c
@@ -48,6 +48,10 @@ static const struct sockopt_test sol_socket_tests[] = {
{ .opt = SO_MARK, .new = 0xeb9f, .expected = 0xeb9f, },
{ .opt = SO_MAX_PACING_RATE, .new = 0xeb9f, .expected = 0xeb9f, },
{ .opt = SO_TXREHASH, .flip = 1, },
+ { .opt = SO_TIMESTAMPING_NEW, .new = SOF_TIMESTAMPING_RX_HARDWARE,
+ .expected = SOF_TIMESTAMPING_RX_HARDWARE, },
+ { .opt = SO_TIMESTAMPING_OLD, .new = SOF_TIMESTAMPING_RX_HARDWARE,
+ .expected = SOF_TIMESTAMPING_RX_HARDWARE, },
{ .opt = 0, },
};
--
2.39.2
