linux.git/include/net/inet_timewait_sock.h, branch v6.1.48

tcp: Add TIME_WAIT sockets in bhash2.

2023-01-12T11:02:15+00:00

[ Upstream commit 936a192f974018b4f6040f6f77b1cc1e75bd8666 ]

Jiri Slaby reported regression of bind() with a simple repro. [0]

The repro creates a TIME_WAIT socket and tries to bind() a new socket
with the same local address and port.  Before commit 28044fc1d495 ("net:
Add a bhash2 table hashed by port and address"), the bind() failed with
-EADDRINUSE, but now it succeeds.

The cited commit should have put TIME_WAIT sockets into bhash2; otherwise,
inet_bhash2_conflict() misses TIME_WAIT sockets when validating bind()
requests if the address is not a wildcard one.

The straight option is to move sk_bind2_node from struct sock to struct
sock_common to add twsk to bhash2 as implemented as RFC. [1]  However, the
binary layout change in the struct sock could affect performances moving
hot fields on different cachelines.

To avoid that, we add another TIME_WAIT list in inet_bind2_bucket and check
it while validating bind().

[0]: https://lore.kernel.org/netdev/6b971a4e-c7d8-411e-1f92-fda29b5b2fb9@kernel.org/
[1]: https://lore.kernel.org/netdev/20221221151258.25748-2-kuniyu@amazon.com/

Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address")
Reported-by: Jiri Slaby 
Suggested-by: Paolo Abeni 
Signed-off-by: Kuniyuki Iwashima 
Acked-by: Joanne Koong 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

Revert "tcp/dccp: get rid of inet_twsk_purge()"

2022-05-13T11:24:12+00:00

This reverts commits:

0dad4087a86a2cbe177404dc73f18ada26a2c390 ("tcp/dccp: get rid of inet_twsk_purge()")
d507204d3c5cc57d9a8bdf0a477615bb59ea1611 ("tcp/dccp: add tw->tw_bslot")

As Leonard pointed out, a newly allocated netns can happen
to reuse a freed 'struct net'.

While TCP TW timers were covered by my patches, other things were not:

1) Lookups in rx path (INET_MATCH() and INET6_MATCH()), as they look
  at 4-tuple plus the 'struct net' pointer.

2) /proc/net/tcp[6] and inet_diag, same reason.

3) hashinfo->bhash[], same reason.

Fixing all this seems risky, lets instead revert.

In the future, we might have a per netns tcp hash table, or
a per netns list of timewait sockets...

Fixes: 0dad4087a86a ("tcp/dccp: get rid of inet_twsk_purge()")
Signed-off-by: Eric Dumazet 
Reported-by: Leonard Crestez 
Tested-by: Leonard Crestez 
Signed-off-by: David S. Miller

tcp/dccp: get rid of inet_twsk_purge()

2022-01-25T11:25:21+00:00

Prior patches in the series made sure tw_timer_handler()
can be fired after netns has been dismantled/freed.

We no longer have to scan a potentially big TCP ehash
table at netns dismantle.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp/dccp: no longer use twsk_net(tw) from tw_timer_handler()

2022-01-25T11:25:21+00:00

We will soon get rid of inet_twsk_purge().

This means that tw_timer_handler() might fire after
a netns has been dismantled/freed.

Instead of adding a function (and data structure) to find a netns
from tw->tw_net_cookie, just update the SNMP counters
a bit earlier, when the netns is known to be alive.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp/dccp: add tw->tw_bslot

2022-01-25T11:25:21+00:00

We want to allow inet_twsk_kill() working even if netns
has been dismantled/freed, to get rid of inet_twsk_purge().

This patch adds tw->tw_bslot to cache the bind bucket slot
so that inet_twsk_kill() no longer needs to dereference twsk_net(tw)

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: honor SO_PRIORITY in TIME_WAIT state

2019-09-27T10:05:02+00:00

ctl packets sent on behalf of TIME_WAIT sockets currently
have a zero skb->priority, which can cause various problems.

In this patch we :

- add a tw_priority field in struct inet_timewait_sock.

- populate it from sk->sk_priority when a TIME_WAIT is created.

- For IPv4, change ip_send_unicast_reply() and its two
  callers to propagate tw_priority correctly.
  ip_send_unicast_reply() no longer changes sk->sk_priority.

- For IPv6, make sure TIME_WAIT sockets pass their tw_priority
  field to tcp_v6_send_response() and tcp_v6_send_ack().

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv6: tcp: send consistent autoflowlabel in TIME_WAIT state

2019-06-10T03:10:19+00:00

In case autoflowlabel is in action, skb_get_hash_flowi6()
derives a non zero skb->hash to the flowlabel.

If skb->hash is zero, a flow dissection is performed.

Since all TCP skbs sent from ESTABLISH state inherit their
skb->hash from sk->sk_txhash, we better keep a copy
of sk->sk_txhash into the TIME_WAIT socket.

After this patch, ACK or RST packets sent on behalf of
a TIME_WAIT socket have the flowlabel that was previously
used by the flow.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman

net-tcp: remove useless tw_timeout field

2018-06-05T14:45:24+00:00

Tested: 'git grep tw_timeout' comes up empty and it builds :-)

Signed-off-by: Maciej Żenczykowski 
Cc: Eric Dumazet 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

tcp: Add mark for TIMEWAIT sockets

2018-05-10T21:44:52+00:00

This version has some suggestions by Eric Dumazet:

- Use a local variable for the mark in IPv6 instead of ctl_sk to avoid SMP
races.
- Use the more elegant "IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark"
statement.
- Factorize code as sk_fullsock() check is not necessary.

Aidan McGurn from Openwave Mobility systems reported the following bug:

"Marked routing is broken on customer deployment. Its effects are large
increase in Uplink retransmissions caused by the client never receiving
the final ACK to their FINACK - this ACK misses the mark and routes out
of the incorrect route."

Currently marks are added to sk_buffs for replies when the "fwmark_reflect"
sysctl is enabled. But not for TW sockets that had sk->sk_mark set via
setsockopt(SO_MARK..).

Fix this in IPv4/v6 by adding tw->tw_mark for TIME_WAIT sockets. Copy the the
original sk->sk_mark in __inet_twsk_hashdance() to the new tw->tw_mark location.
Then progate this so that the skb gets sent with the correct mark. Do the same
for resets. Give the "fwmark_reflect" sysctl precedence over sk->sk_mark so that
netfilter rules are still honored.

Signed-off-by: Jon Maxwell 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller