netdev - Re: [PATCH net-next v2 2/2] net: make SOF_TIMESTAMPING_RX

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <66d083d24aa8c_3895fa294d5@willemb.c.googlers.com.notmuch>
Date: Thu, 29 Aug 2024 10:21:06 -0400
From: Willem de Bruijn <willemdebruijn.kernel@...il.com>
To: Jason Xing <kerneljasonxing@...il.com>, 
 davem@...emloft.net, 
 edumazet@...gle.com, 
 kuba@...nel.org, 
 pabeni@...hat.com, 
 dsahern@...nel.org, 
 willemb@...gle.com
Cc: netdev@...r.kernel.org, 
 Jason Xing <kernelxing@...cent.com>, 
 Willem de Bruijn <willemdebruijn.kernel@...il.com>
Subject: Re: [PATCH net-next v2 2/2] net: make SOF_TIMESTAMPING_RX_SOFTWARE
 feature per socket

Jason Xing wrote:
> From: Jason Xing <kernelxing@...cent.com>
> 
> Like the previous patch in this series, we need to make sure that
> we both set SOF_TIMESTAMPING_SOFTWARE and SOF_TIMESTAMPING_RX_SOFTWARE
> flags together so that we can let the user parse the rx timestamp.
> 
> One more important and special thing is that we should take care of
> errqueue recv path because we rely on errqueue to get our timestamps
> for sendmsg(). Or else, If the user wants to read when setting
> SOF_TIMESTAMPING_TX_ACK, something like this, we cannot get timestamps,
> for example, in TCP case. So we should consider those
> SOF_TIMESTAMPING_TX_* flags.
> 
> After this patch, we are able to pass the testcase 6 for IP and UDP
> cases when running ./rxtimestamp binary.
> 
> Cc: Willem de Bruijn <willemdebruijn.kernel@...il.com>
> Signed-off-by: Jason Xing <kernelxing@...cent.com>
> ---
>  Documentation/networking/timestamping.rst |  7 +++++++
>  include/net/sock.h                        |  7 ++++---
>  net/bluetooth/hci_sock.c                  |  4 ++--
>  net/core/sock.c                           |  2 +-
>  net/ipv4/ip_sockglue.c                    |  2 +-
>  net/ipv4/ping.c                           |  2 +-
>  net/ipv6/datagram.c                       |  4 ++--
>  net/l2tp/l2tp_ip.c                        |  2 +-
>  net/l2tp/l2tp_ip6.c                       |  2 +-
>  net/nfc/llcp_sock.c                       |  2 +-
>  net/rxrpc/recvmsg.c                       |  2 +-
>  net/socket.c                              | 11 ++++++++---
>  net/unix/af_unix.c                        |  2 +-
>  13 files changed, 31 insertions(+), 18 deletions(-)
> 
> diff --git a/Documentation/networking/timestamping.rst b/Documentation/networking/timestamping.rst
> index 5e93cd71f99f..93378b78c6dd 100644
> --- a/Documentation/networking/timestamping.rst
> +++ b/Documentation/networking/timestamping.rst
> @@ -160,6 +160,13 @@ SOF_TIMESTAMPING_RAW_HARDWARE:
>    Report hardware timestamps as generated by
>    SOF_TIMESTAMPING_TX_HARDWARE when available.
>  
> +Please note: previously, if an application starts first which turns on
> +netstamp_needed_key, then another one only passing SOF_TIMESTAMPING_SOFTWARE
> +could also get rx timestamp. Now we handle this case and will not get
> +rx timestamp under this circumstance. We encourage that for each socket
> +we should use the SOF_TIMESTAMPING_RX_SOFTWARE generation flag to time
> +stamp the skb and use SOF_TIMESTAMPING_SOFTWARE report flag to tell
> +the application.

Don't mention previously. Readers will not be aware of when this
Documentation was added.

Also, nit: no "Please note". Else every paragraph can start with that,
as each statement should be noteworthy.

>  
>  1.3.3 Timestamp Options
>  ^^^^^^^^^^^^^^^^^^^^^^^
> diff --git a/include/net/sock.h b/include/net/sock.h
> index cce23ac4d514..b8535692f340 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -2600,12 +2600,13 @@ static inline void sock_write_timestamp(struct sock *sk, ktime_t kt)
>  }
>  
>  void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
> -			   struct sk_buff *skb);
> +			   struct sk_buff *skb, bool errqueue);
>  void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
>  			     struct sk_buff *skb);

I suspect that the direction, ingress or egress, and thus whether the
timestamp is to be queued on the error queue or not, can be inferred
without exceptions from skb->pkt_type == PACKET_OUTGOING.

That would avoid all this boilerplate argument passing.