Subject: Re: [PATCH net-next 3/3] ipv4: Create probe timer for tcp PMTU as per RFC4821

From: Fan Du <[email-masked]>
Date: Mon, 16 Feb 2015 13:38:43 +0800

于 2015年02月13日 20:31, Eric Dumazet 写道:
> On Fri, 2015-02-13 at 16:16 +0800, Fan Du wrote:
>> >As per RFC4821 7.3.  Selecting Probe Size, a probe timer should
>> >be armed once probing has converged. Once this timer expired,
>> >probing again to take advantage of any path PMTU change. The
>> >recommended probing interval is 10 minutes per RFC1981.
>> >
>> >Signed-off-by: Fan Du<[email-masked]>
>> >---
>> >  include/net/inet_connection_sock.h |    2 ++
>> >  include/net/netns/ipv4.h           |    1 +
>> >  include/net/tcp.h                  |    3 +++
>> >  net/ipv4/sysctl_net_ipv4.c         |    7 +++++++
>> >  net/ipv4/tcp.c                     |    2 ++
>> >  net/ipv4/tcp_ipv4.c                |    1 +
>> >  net/ipv4/tcp_output.c              |   23 ++++++++++++++++++++++-
>> >  7 files changed, 38 insertions(+), 1 deletions(-)
>> >
>> >diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
>> >index 3d0932e..e78e5ab 100644
>> >--- a/include/net/inet_connection_sock.h
>> >+++ b/include/net/inet_connection_sock.h
>> >@@ -126,6 +126,8 @@ struct inet_connection_sock {
>> >
>> >  		int		  search_high_sav;
>> >  		int		  search_low_sav;
>> >+
>> >+		struct timer_list probe_timer;
>> >
> We certainly wont add yet another timer in tcp socket for such usage.
>
> And a buggy one, since you forgot all the refcounting associated with
> such timers.

oh, embarrassing...
Will place probe timer aside with icsk_delack_timer in struct inet_connection_sock,
and manipulate through sk_reset_timer.

Thanks for the reviewing.