diff options
| author | Willem de Bruijn <willemb@google.com> | 2022-12-07 09:37:01 -0500 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-12-08 19:49:21 -0800 |
| commit | b534dc46c8ae0165b1b2509be24dbea4fa9c4011 (patch) | |
| tree | fb5430445edefccc6a6a9c79c5a20cb95912e516 /include/net | |
| parent | ecd6df3c1ba8ad8befd82fc8f0d2438e8d3c75cc (diff) | |
net_tstamp: add SOF_TIMESTAMPING_OPT_ID_TCP
Add an option to initialize SOF_TIMESTAMPING_OPT_ID for TCP from
write_seq sockets instead of snd_una.
This should have been the behavior from the start. Because processes
may now exist that rely on the established behavior, do not change
behavior of the existing option, but add the right behavior with a new
flag. It is encouraged to always set SOF_TIMESTAMPING_OPT_ID_TCP on
stream sockets along with the existing SOF_TIMESTAMPING_OPT_ID.
Intuitively the contract is that the counter is zero after the
setsockopt, so that the next write N results in a notification for
the last byte N - 1.
On idle sockets snd_una == write_seq and this holds for both. But on
sockets with data in transmission, snd_una records the unacked offset
in the stream. This depends on the ACK response from the peer. A
process cannot learn this in a race free manner (ioctl SIOCOUTQ is one
racy approach).
write_seq records the offset at the last byte written by the process.
This is a better starting point. It matches the intuitive contract in
all circumstances, unaffected by external behavior.
The new timestamp flag necessitates increasing sk_tsflags to 32 bits.
Move the field in struct sock to avoid growing the socket (for some
common CONFIG variants). The UAPI interface so_timestamping.flags is
already int, so 32 bits wide.
Reported-by: Sotirios Delimanolis <sotodel@meta.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20221207143701.29861-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/sock.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 6d207e7c4ad0..ecea3dcc2217 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -503,10 +503,10 @@ struct sock { #if BITS_PER_LONG==32 seqlock_t sk_stamp_seq; #endif - u16 sk_tsflags; - u8 sk_shutdown; atomic_t sk_tskey; atomic_t sk_zckey; + u32 sk_tsflags; + u8 sk_shutdown; u8 sk_clockid; u8 sk_txtime_deadline_mode : 1, @@ -1899,7 +1899,7 @@ static inline void sock_replace_proto(struct sock *sk, struct proto *proto) struct sockcm_cookie { u64 transmit_time; u32 mark; - u16 tsflags; + u32 tsflags; }; static inline void sockcm_init(struct sockcm_cookie *sockc, |