Skip to content

Commit

Permalink
Merge branch 'net-timestamp-introduce-a-flag-to-filter-out-rx-softwar…
Browse files Browse the repository at this point in the history 
…e-and-hardware-report'

Jason Xing says:

====================
net-timestamp: introduce a flag to filter out rx software and hardware report

When one socket is set SOF_TIMESTAMPING_RX_SOFTWARE which means the
whole system turns on the netstamp_needed_key button, other sockets
that only have SOF_TIMESTAMPING_SOFTWARE will be affected and then
print the rx timestamp information even without setting
SOF_TIMESTAMPING_RX_SOFTWARE generation flag.

How to solve it without breaking users?
We introduce a new flag named SOF_TIMESTAMPING_OPT_RX_FILTER. Using
it together with SOF_TIMESTAMPING_SOFTWARE can stop reporting the
rx software timestamp.

Similarly, we also filter out the hardware case where one process
enables the rx hardware generation flag, then another process only
passing SOF_TIMESTAMPING_RAW_HARDWARE gets the timestamp. So we can set
both SOF_TIMESTAMPING_RAW_HARDWARE and SOF_TIMESTAMPING_OPT_RX_FILTER
to stop reporting rx hardware timestamp after this patch applied.

v6: https://lore.kernel.org/20240906095640.77533-1-kerneljasonxing@gmail.com
v5: https://lore.kernel.org/20240905071738.3725-1-kerneljasonxing@gmail.com
v4: https://lore.kernel.org/20240830153751.86895-1-kerneljasonxing@gmail.com
v3: https://lore.kernel.org/20240828160145.68805-1-kerneljasonxing@gmail.com
v2: https://lore.kernel.org/20240825152440.93054-1-kerneljasonxing@gmail.com
====================

Link: https://patch.msgid.link/20240909015612.3856-1-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  • Loading branch information
Jakub Kicinski committed Sep 10, 2024
2 parents e503f82 + fffe8ef commit 97b1ebb
Show file tree
Hide file tree
Showing 6 changed files with 53 additions and 5 deletions.
17 changes: 17 additions & 0 deletions Documentation/networking/timestamping.rst
View file
Original file line number Diff line number Diff line change
Expand Up @@ -267,6 +267,23 @@ SOF_TIMESTAMPING_OPT_TX_SWHW:
two separate messages will be looped to the socket's error queue,
each containing just one timestamp.

SOF_TIMESTAMPING_OPT_RX_FILTER:
Filter out spurious receive timestamps: report a receive timestamp
only if the matching timestamp generation flag is enabled.

Receive timestamps are generated early in the ingress path, before a
packet's destination socket is known. If any socket enables receive
timestamps, packets for all socket will receive timestamped packets.
Including those that request timestamp reporting with
SOF_TIMESTAMPING_SOFTWARE and/or SOF_TIMESTAMPING_RAW_HARDWARE, but
do not request receive timestamp generation. This can happen when
requesting transmit timestamps only.

Receiving spurious timestamps is generally benign. A process can
ignore the unexpected non-zero value. But it makes behavior subtly
dependent on other sockets. This flag isolates the socket for more
deterministic behavior.

New applications are encouraged to pass SOF_TIMESTAMPING_OPT_ID to
disambiguate timestamps and SOF_TIMESTAMPING_OPT_TSONLY to operate
regardless of the setting of sysctl net.core.tstamp_allow_data.
Expand Down
3 changes: 2 additions & 1 deletion include/uapi/linux/net_tstamp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,8 +32,9 @@ enum {
SOF_TIMESTAMPING_OPT_TX_SWHW = (1<<14),
SOF_TIMESTAMPING_BIND_PHC = (1 << 15),
SOF_TIMESTAMPING_OPT_ID_TCP = (1 << 16),
SOF_TIMESTAMPING_OPT_RX_FILTER = (1 << 17),

SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_ID_TCP,
SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_RX_FILTER,
SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) |
SOF_TIMESTAMPING_LAST
};
Expand Down
1 change: 1 addition & 0 deletions net/ethtool/common.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -427,6 +427,7 @@ const char sof_timestamping_names[][ETH_GSTRING_LEN] = {
[const_ilog2(SOF_TIMESTAMPING_OPT_TX_SWHW)] = "option-tx-swhw",
[const_ilog2(SOF_TIMESTAMPING_BIND_PHC)] = "bind-phc",
[const_ilog2(SOF_TIMESTAMPING_OPT_ID_TCP)] = "option-id-tcp",
[const_ilog2(SOF_TIMESTAMPING_OPT_RX_FILTER)] = "option-rx-filter",
};
static_assert(ARRAY_SIZE(sof_timestamping_names) == __SOF_TIMESTAMPING_CNT);

Expand Down
9 changes: 7 additions & 2 deletions net/ipv4/tcp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2235,6 +2235,7 @@ void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
struct scm_timestamping_internal *tss)
{
int new_tstamp = sock_flag(sk, SOCK_TSTAMP_NEW);
u32 tsflags = READ_ONCE(sk->sk_tsflags);
bool has_timestamping = false;

if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) {
Expand Down Expand Up @@ -2274,14 +2275,18 @@ void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
}
}

if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_SOFTWARE)
if (tsflags & SOF_TIMESTAMPING_SOFTWARE &&
(tsflags & SOF_TIMESTAMPING_RX_SOFTWARE ||
!(tsflags & SOF_TIMESTAMPING_OPT_RX_FILTER)))
has_timestamping = true;
else
tss->ts[0] = (struct timespec64) {0};
}

if (tss->ts[2].tv_sec || tss->ts[2].tv_nsec) {
if (READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_RAW_HARDWARE)
if (tsflags & SOF_TIMESTAMPING_RAW_HARDWARE &&
(tsflags & SOF_TIMESTAMPING_RX_HARDWARE ||
!(tsflags & SOF_TIMESTAMPING_OPT_RX_FILTER)))
has_timestamping = true;
else
tss->ts[2] = (struct timespec64) {0};
Expand Down
10 changes: 8 additions & 2 deletions net/socket.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -946,11 +946,17 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,

memset(&tss, 0, sizeof(tss));
tsflags = READ_ONCE(sk->sk_tsflags);
if ((tsflags & SOF_TIMESTAMPING_SOFTWARE) &&
if ((tsflags & SOF_TIMESTAMPING_SOFTWARE &&
(tsflags & SOF_TIMESTAMPING_RX_SOFTWARE ||
skb_is_err_queue(skb) ||
!(tsflags & SOF_TIMESTAMPING_OPT_RX_FILTER))) &&
ktime_to_timespec64_cond(skb->tstamp, tss.ts + 0))
empty = 0;
if (shhwtstamps &&
(tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) &&
(tsflags & SOF_TIMESTAMPING_RAW_HARDWARE &&
(tsflags & SOF_TIMESTAMPING_RX_HARDWARE ||
skb_is_err_queue(skb) ||
!(tsflags & SOF_TIMESTAMPING_OPT_RX_FILTER))) &&
!skb_is_swtx_tstamp(skb, false_tstamp)) {
if_index = 0;
if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP_NETDEV)
Expand Down
18 changes: 18 additions & 0 deletions tools/testing/selftests/net/rxtimestamp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,8 @@ static struct sof_flag sof_flags[] = {
SOF_FLAG(SOF_TIMESTAMPING_SOFTWARE),
SOF_FLAG(SOF_TIMESTAMPING_RX_SOFTWARE),
SOF_FLAG(SOF_TIMESTAMPING_RX_HARDWARE),
SOF_FLAG(SOF_TIMESTAMPING_OPT_RX_FILTER),
SOF_FLAG(SOF_TIMESTAMPING_RAW_HARDWARE),
};

static struct socket_type socket_types[] = {
Expand Down Expand Up @@ -97,6 +99,22 @@ static struct test_case test_cases[] = {
| SOF_TIMESTAMPING_RX_HARDWARE },
{}
},
{
{ .so_timestamping = SOF_TIMESTAMPING_RAW_HARDWARE
| SOF_TIMESTAMPING_OPT_RX_FILTER },
{}
},
{
{ .so_timestamping = SOF_TIMESTAMPING_SOFTWARE
| SOF_TIMESTAMPING_OPT_RX_FILTER },
{}
},
{
{ .so_timestamping = SOF_TIMESTAMPING_SOFTWARE
| SOF_TIMESTAMPING_RX_SOFTWARE
| SOF_TIMESTAMPING_OPT_RX_FILTER },
{ .swtstamp = true }
},
{
{ .so_timestamping = SOF_TIMESTAMPING_SOFTWARE
| SOF_TIMESTAMPING_RX_SOFTWARE },
Expand Down

0 comments on commit 97b1ebb

Please sign in to comment.