linux-stable.git/net/ipv4/datagram.c, branch linux-6.0.y Linux kernel stable tree udp: Update reuse->has_conns under reuseport_lock. 2022-10-29T08:08:33+00:00 Kuniyuki Iwashima kuniyu@amazon.com 2022-10-14T18:26:25+00:00 1fb3a672317fba2a54f1bc8a6401235c6f11f883 [ Upstream commit 69421bf98482d089e50799f45e48b25ce4a8d154 ] When we call connect() for a UDP socket in a reuseport group, we have to update sk->sk_reuseport_cb->has_conns to 1. Otherwise, the kernel could select a unconnected socket wrongly for packets sent to the connected socket. However, the current way to set has_conns is illegal and possible to trigger that problem. reuseport_has_conns() changes has_conns under rcu_read_lock(), which upgrades the RCU reader to the updater. Then, it must do the update under the updater's lock, reuseport_lock, but it doesn't for now. For this reason, there is a race below where we fail to set has_conns resulting in the wrong socket selection. To avoid the race, let's split the reader and updater with proper locking. cpu1 cpu2 +----+ +----+ __ip[46]_datagram_connect() reuseport_grow() . . |- reuseport_has_conns(sk, true) |- more_reuse = __reuseport_alloc(more_socks_size) | . | | |- rcu_read_lock() | |- reuse = rcu_dereference(sk->sk_reuseport_cb) | | | | | /* reuse->has_conns == 0 here */ | | |- more_reuse->has_conns = reuse->has_conns | |- reuse->has_conns = 1 | /* more_reuse->has_conns SHOULD BE 1 HERE */ | | | | | |- rcu_assign_pointer(reuse->socks[i]->sk_reuseport_cb, | | | more_reuse) | `- rcu_read_unlock() `- kfree_rcu(reuse, rcu) | |- sk->sk_state = TCP_ESTABLISHED Note the likely(reuse) in reuseport_has_conns_set() is always true, but we put the test there for ease of review. [0] For the record, usually, sk_reuseport_cb is changed under lock_sock(). The only exception is reuseport_grow() & TCP reqsk migration case. 1) shutdown() TCP listener, which is moved into the latter part of reuse->socks[] to migrate reqsk. 2) New listen() overflows reuse->socks[] and call reuseport_grow(). 3) reuse->max_socks overflows u16 with the new listener. 4) reuseport_grow() pops the old shutdown()ed listener from the array and update its sk->sk_reuseport_cb as NULL without lock_sock(). shutdown()ed TCP sk->sk_reuseport_cb can be changed without lock_sock(), but, reuseport_has_conns_set() is called only for UDP under lock_sock(), so likely(reuse) never be false in reuseport_has_conns_set(). [0]: https://lore.kernel.org/netdev/CANn89iLja=eQHbsM_Ta2sQF0tOGU8vAGrh_izRuuHjuO1ouUag@mail.gmail.com/ Fixes: acdcecc61285 ("udp: correct reuseport selection with connected sockets") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20221014182625.89913-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 69421bf98482d089e50799f45e48b25ce4a8d154 ]

When we call connect() for a UDP socket in a reuseport group, we have
to update sk->sk_reuseport_cb->has_conns to 1.  Otherwise, the kernel
could select a unconnected socket wrongly for packets sent to the
connected socket.

However, the current way to set has_conns is illegal and possible to
trigger that problem.  reuseport_has_conns() changes has_conns under
rcu_read_lock(), which upgrades the RCU reader to the updater.  Then,
it must do the update under the updater's lock, reuseport_lock, but
it doesn't for now.

For this reason, there is a race below where we fail to set has_conns
resulting in the wrong socket selection.  To avoid the race, let's split
the reader and updater with proper locking.

 cpu1                               cpu2
+----+                             +----+

__ip[46]_datagram_connect()        reuseport_grow()
.                                  .
|- reuseport_has_conns(sk, true)   |- more_reuse = __reuseport_alloc(more_socks_size)
|  .                               |
|  |- rcu_read_lock()
|  |- reuse = rcu_dereference(sk->sk_reuseport_cb)
|  |
|  |                               |  /* reuse->has_conns == 0 here */
|  |                               |- more_reuse->has_conns = reuse->has_conns
|  |- reuse->has_conns = 1         |  /* more_reuse->has_conns SHOULD BE 1 HERE */
|  |                               |
|  |                               |- rcu_assign_pointer(reuse->socks[i]->sk_reuseport_cb,
|  |                               |                     more_reuse)
|  `- rcu_read_unlock()            `- kfree_rcu(reuse, rcu)
|
|- sk->sk_state = TCP_ESTABLISHED

Note the likely(reuse) in reuseport_has_conns_set() is always true,
but we put the test there for ease of review.  [0]

For the record, usually, sk_reuseport_cb is changed under lock_sock().
The only exception is reuseport_grow() & TCP reqsk migration case.

  1) shutdown() TCP listener, which is moved into the latter part of
     reuse->socks[] to migrate reqsk.

  2) New listen() overflows reuse->socks[] and call reuseport_grow().

  3) reuse->max_socks overflows u16 with the new listener.

  4) reuseport_grow() pops the old shutdown()ed listener from the array
     and update its sk->sk_reuseport_cb as NULL without lock_sock().

shutdown()ed TCP sk->sk_reuseport_cb can be changed without lock_sock(),
but, reuseport_has_conns_set() is called only for UDP under lock_sock(),
so likely(reuse) never be false in reuseport_has_conns_set().

[0]: https://lore.kernel.org/netdev/CANn89iLja=eQHbsM_Ta2sQF0tOGU8vAGrh_izRuuHjuO1ouUag@mail.gmail.com/

Fixes: acdcecc61285 ("udp: correct reuseport selection with connected sockets")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20221014182625.89913-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net-next: Fix IP_UNICAST_IF option behavior for connected sockets 2022-10-21T10:39:07+00:00 Richard Gobert richardbgobert@gmail.com 2022-08-29T11:18:51+00:00 45304d0db4b592343d753ef922f96ef0ceed62ab [ Upstream commit 0e4d354762cefd3e16b4cff8988ff276e45effc4 ] The IP_UNICAST_IF socket option is used to set the outgoing interface for outbound packets. The IP_UNICAST_IF socket option was added as it was needed by the Wine project, since no other existing option (SO_BINDTODEVICE socket option, IP_PKTINFO socket option or the bind function) provided the needed characteristics needed by the IP_UNICAST_IF socket option. [1] The IP_UNICAST_IF socket option works well for unconnected sockets, that is, the interface specified by the IP_UNICAST_IF socket option is taken into consideration in the route lookup process when a packet is being sent. However, for connected sockets, the outbound interface is chosen when connecting the socket, and in the route lookup process which is done when a packet is being sent, the interface specified by the IP_UNICAST_IF socket option is being ignored. This inconsistent behavior was reported and discussed in an issue opened on systemd's GitHub project [2]. Also, a bug report was submitted in the kernel's bugzilla [3]. To understand the problem in more detail, we can look at what happens for UDP packets over IPv4 (The same analysis was done separately in the referenced systemd issue). When a UDP packet is sent the udp_sendmsg function gets called and the following happens: 1. The oif member of the struct ipcm_cookie ipc (which stores the output interface of the packet) is initialized by the ipcm_init_sk function to inet->sk.sk_bound_dev_if (the device set by the SO_BINDTODEVICE socket option). 2. If the IP_PKTINFO socket option was set, the oif member gets overridden by the call to the ip_cmsg_send function. 3. If no output interface was selected yet, the interface specified by the IP_UNICAST_IF socket option is used. 4. If the socket is connected and no destination address is specified in the send function, the struct ipcm_cookie ipc is not taken into consideration and the cached route, that was calculated in the connect function is being used. Thus, for a connected socket, the IP_UNICAST_IF sockopt isn't taken into consideration. This patch corrects the behavior of the IP_UNICAST_IF socket option for connect()ed sockets by taking into consideration the IP_UNICAST_IF sockopt when connecting the socket. In order to avoid reconnecting the socket, this option is still ignored when applied on an already connected socket until connect() is called again by the Richard Gobert. Change the __ip4_datagram_connect function, which is called during socket connection, to take into consideration the interface set by the IP_UNICAST_IF socket option, in a similar way to what is done in the udp_sendmsg function. [1] https://lore.kernel.org/netdev/1328685717.4736.4.camel@edumazet-laptop/T/ [2] https://github.com/systemd/systemd/issues/11935#issuecomment-618691018 [3] https://bugzilla.kernel.org/show_bug.cgi?id=210255 Signed-off-by: Richard Gobert <richardbgobert@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20220829111554.GA1771@debian Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 0e4d354762cefd3e16b4cff8988ff276e45effc4 ]

The IP_UNICAST_IF socket option is used to set the outgoing interface
for outbound packets.

The IP_UNICAST_IF socket option was added as it was needed by the
Wine project, since no other existing option (SO_BINDTODEVICE socket
option, IP_PKTINFO socket option or the bind function) provided the
needed characteristics needed by the IP_UNICAST_IF socket option. [1]
The IP_UNICAST_IF socket option works well for unconnected sockets,
that is, the interface specified by the IP_UNICAST_IF socket option
is taken into consideration in the route lookup process when a packet
is being sent. However, for connected sockets, the outbound interface
is chosen when connecting the socket, and in the route lookup process
which is done when a packet is being sent, the interface specified by
the IP_UNICAST_IF socket option is being ignored.

This inconsistent behavior was reported and discussed in an issue
opened on systemd's GitHub project [2]. Also, a bug report was
submitted in the kernel's bugzilla [3].

To understand the problem in more detail, we can look at what happens
for UDP packets over IPv4 (The same analysis was done separately in
the referenced systemd issue).
When a UDP packet is sent the udp_sendmsg function gets called and
the following happens:

1. The oif member of the struct ipcm_cookie ipc (which stores the
output interface of the packet) is initialized by the ipcm_init_sk
function to inet->sk.sk_bound_dev_if (the device set by the
SO_BINDTODEVICE socket option).

2. If the IP_PKTINFO socket option was set, the oif member gets
overridden by the call to the ip_cmsg_send function.

3. If no output interface was selected yet, the interface specified
by the IP_UNICAST_IF socket option is used.

4. If the socket is connected and no destination address is
specified in the send function, the struct ipcm_cookie ipc is not
taken into consideration and the cached route, that was calculated in
the connect function is being used.

Thus, for a connected socket, the IP_UNICAST_IF sockopt isn't taken
into consideration.

This patch corrects the behavior of the IP_UNICAST_IF socket option
for connect()ed sockets by taking into consideration the
IP_UNICAST_IF sockopt when connecting the socket.

In order to avoid reconnecting the socket, this option is still
ignored when applied on an already connected socket until connect()
is called again by the Richard Gobert.

Change the __ip4_datagram_connect function, which is called during
socket connection, to take into consideration the interface set by
the IP_UNICAST_IF socket option, in a similar way to what is done in
the udp_sendmsg function.

[1] https://lore.kernel.org/netdev/1328685717.4736.4.camel@edumazet-laptop/T/
[2] https://github.com/systemd/systemd/issues/11935#issuecomment-618691018
[3] https://bugzilla.kernel.org/show_bug.cgi?id=210255

Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220829111554.GA1771@debian
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipv4: Avoid using RTO_ONLINK with ip_route_connect(). 2022-04-22T12:06:03+00:00 Guillaume Nault gnault@redhat.com 2022-04-20T23:21:33+00:00 67e1e2f4854bb2c0dd2b8440cf090016a0e1a091 Now that ip_rt_fix_tos() doesn't reset ->flowi4_scope unconditionally, we don't have to rely on the RTO_ONLINK bit to properly set the scope of a flowi4 structure. We can just set ->flowi4_scope explicitly and avoid using RTO_ONLINK in ->flowi4_tos. This patch converts callers of ip_route_connect(). Instead of setting the tos parameter with RT_CONN_FLAGS(sk), as all callers do, we can: 1- Drop the tos parameter from ip_route_connect(): its value was entirely based on sk, which is also passed as parameter. 2- Set ->flowi4_scope depending on the SOCK_LOCALROUTE socket option instead of always initialising it with RT_SCOPE_UNIVERSE (let's define ip_sock_rt_scope() for this purpose). 3- Avoid overloading ->flowi4_tos with RTO_ONLINK: since the scope is now properly initialised, we don't need to tell ip_rt_fix_tos() to adjust ->flowi4_scope for us. So let's define ip_sock_rt_tos(), which is the same as RT_CONN_FLAGS() but without the RTO_ONLINK bit overload. Note: In the original ip_route_connect() code, __ip_route_output_key() might clear the RTO_ONLINK bit of fl4->flowi4_tos (because of ip_rt_fix_tos()). Therefore flowi4_update_output() had to reuse the original tos variable. Now that we don't set RTO_ONLINK any more, this is not a problem and we can use fl4->flowi4_tos in flowi4_update_output(). Signed-off-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Now that ip_rt_fix_tos() doesn't reset ->flowi4_scope unconditionally,
we don't have to rely on the RTO_ONLINK bit to properly set the scope
of a flowi4 structure. We can just set ->flowi4_scope explicitly and
avoid using RTO_ONLINK in ->flowi4_tos.

This patch converts callers of ip_route_connect(). Instead of setting
the tos parameter with RT_CONN_FLAGS(sk), as all callers do, we can:

  1- Drop the tos parameter from ip_route_connect(): its value was
     entirely based on sk, which is also passed as parameter.

  2- Set ->flowi4_scope depending on the SOCK_LOCALROUTE socket option
     instead of always initialising it with RT_SCOPE_UNIVERSE (let's
     define ip_sock_rt_scope() for this purpose).

  3- Avoid overloading ->flowi4_tos with RTO_ONLINK: since the scope is
     now properly initialised, we don't need to tell ip_rt_fix_tos() to
     adjust ->flowi4_scope for us. So let's define ip_sock_rt_tos(),
     which is the same as RT_CONN_FLAGS() but without the RTO_ONLINK
     bit overload.

Note:
  In the original ip_route_connect() code, __ip_route_output_key()
  might clear the RTO_ONLINK bit of fl4->flowi4_tos (because of
  ip_rt_fix_tos()). Therefore flowi4_update_output() had to reuse the
  original tos variable. Now that we don't set RTO_ONLINK any more,
  this is not a problem and we can use fl4->flowi4_tos in
  flowi4_update_output().

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/datagram.c: remove superfluous header files from datagram.c 2021-09-29T10:39:33+00:00 Mianhan Liu liumh1@shanghaitech.edu.cn 2021-09-29T05:31:09+00:00 6a832a6c72b9365299406f13c799b63dafe03677 datagram.c hasn't use any macro or function declared in linux/ip.h. Thus, these files can be removed from datagram.c safely without affecting the compilation of the net/ipv4 module Signed-off-by: Mianhan Liu <liumh1@shanghaitech.edu.cn> Signed-off-by: David S. Miller <davem@davemloft.net> 
datagram.c hasn't use any macro or function declared in linux/ip.h.
Thus, these files can be removed from datagram.c safely without
affecting the compilation of the net/ipv4 module

Signed-off-by: Mianhan Liu <liumh1@shanghaitech.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
inet: stop leaking jiffies on the wire 2019-11-01T21:57:52+00:00 Eric Dumazet edumazet@google.com 2019-11-01T17:32:19+00:00 a904a0693c189691eeee64f6c6b188bd7dc244e9 Historically linux tried to stick to RFC 791, 1122, 2003 for IPv4 ID field generation. RFC 6864 made clear that no matter how hard we try, we can not ensure unicity of IP ID within maximum lifetime for all datagrams with a given source address/destination address/protocol tuple. Linux uses a per socket inet generator (inet_id), initialized at connection startup with a XOR of 'jiffies' and other fields that appear clear on the wire. Thiemo Nagel pointed that this strategy is a privacy concern as this provides 16 bits of entropy to fingerprint devices. Let's switch to a random starting point, this is just as good as far as RFC 6864 is concerned and does not leak anything critical. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Thiemo Nagel <tnagel@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Historically linux tried to stick to RFC 791, 1122, 2003
for IPv4 ID field generation.

RFC 6864 made clear that no matter how hard we try,
we can not ensure unicity of IP ID within maximum
lifetime for all datagrams with a given source
address/destination address/protocol tuple.

Linux uses a per socket inet generator (inet_id), initialized
at connection startup with a XOR of 'jiffies' and other
fields that appear clear on the wire.

Thiemo Nagel pointed that this strategy is a privacy
concern as this provides 16 bits of entropy to fingerprint
devices.

Let's switch to a random starting point, this is just as
good as far as RFC 6864 is concerned and does not leak
anything critical.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Thiemo Nagel <tnagel@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
udp: correct reuseport selection with connected sockets 2019-09-16T07:02:18+00:00 Willem de Bruijn willemb@google.com 2019-09-13T01:16:39+00:00 acdcecc61285faed359f1a3568c32089cc3a8329 UDP reuseport groups can hold a mix unconnected and connected sockets. Ensure that connections only receive all traffic to their 4-tuple. Fast reuseport returns on the first reuseport match on the assumption that all matches are equal. Only if connections are present, return to the previous behavior of scoring all sockets. Record if connections are present and if so (1) treat such connected sockets as an independent match from the group, (2) only return 2-tuple matches from reuseport and (3) do not return on the first 2-tuple reuseport match to allow for a higher scoring match later. New field has_conns is set without locks. No other fields in the bitmap are modified at runtime and the field is only ever set unconditionally, so an RMW cannot miss a change. Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection") Link: http://lkml.kernel.org/r/CA+FuTSfRP09aJNYRt04SS6qj22ViiOEWaWmLAwX0psk8-PGNxw@mail.gmail.com Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Craig Gallek <kraig@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
UDP reuseport groups can hold a mix unconnected and connected sockets.
Ensure that connections only receive all traffic to their 4-tuple.

Fast reuseport returns on the first reuseport match on the assumption
that all matches are equal. Only if connections are present, return to
the previous behavior of scoring all sockets.

Record if connections are present and if so (1) treat such connected
sockets as an independent match from the group, (2) only return
2-tuple matches from reuseport and (3) do not return on the first
2-tuple reuseport match to allow for a higher scoring match later.

New field has_conns is set without locks. No other fields in the
bitmap are modified at runtime and the field is only ever set
unconditionally, so an RMW cannot miss a change.

Fixes: e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection")
Link: http://lkml.kernel.org/r/CA+FuTSfRP09aJNYRt04SS6qj22ViiOEWaWmLAwX0psk8-PGNxw@mail.gmail.com
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Craig Gallek <kraig@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30T18:26:32+00:00 Thomas Gleixner tglx@linutronix.de 2019-05-27T06:55:01+00:00 2874c5fd284268364ece81a7bd936f3c8168e567 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 <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
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 <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ipv4: Allow sending multicast packets on specific i/f using VRF socket 2018-10-03T05:28:17+00:00 Robert Shearman rshearma@vyatta.att-mail.com 2018-10-01T08:40:23+00:00 854da991733d1b4f60042423875e32be7f8f0421 It is useful to be able to use the same socket for listening in a specific VRF, as for sending multicast packets out of a specific interface. However, the bound device on the socket currently takes precedence and results in the packets not being sent. Relax the condition on overriding the output interface to use for sending packets out of UDP, raw and ping sockets to allow multicast packets to be sent using the specified multicast interface. Signed-off-by: Robert Shearman <rshearma@vyatta.att-mail.com> Signed-off-by: Mike Manning <mmanning@vyatta.att-mail.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
It is useful to be able to use the same socket for listening in a
specific VRF, as for sending multicast packets out of a specific
interface. However, the bound device on the socket currently takes
precedence and results in the packets not being sent.

Relax the condition on overriding the output interface to use for
sending packets out of UDP, raw and ping sockets to allow multicast
packets to be sent using the specified multicast interface.

Signed-off-by: Robert Shearman <rshearma@vyatta.att-mail.com>
Signed-off-by: Mike Manning <mmanning@vyatta.att-mail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: Set sk_txhash from a random number 2015-07-30T05:44:04+00:00 Tom Herbert tom@herbertland.com 2015-07-28T23:02:05+00:00 877d1f6291f8e391237e324be58479a3e3a7407c This patch creates sk_set_txhash and eliminates protocol specific inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a random number instead of performing flow dissection. sk_set_txash is also allowed to be called multiple times for the same socket, we'll need this when redoing the hash for negative routing advice. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
This patch creates sk_set_txhash and eliminates protocol specific
inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a
random number instead of performing flow dissection. sk_set_txash
is also allowed to be called multiple times for the same socket,
we'll need this when redoing the hash for negative routing advice.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv6: lock socket in ip6_datagram_connect() 2015-07-16T00:25:51+00:00 Eric Dumazet edumazet@google.com 2015-07-14T06:10:22+00:00 03645a11a570d52e70631838cb786eb4253eb463 ip6_datagram_connect() is doing a lot of socket changes without socket being locked. This looks wrong, at least for udp_lib_rehash() which could corrupt lists because of concurrent udp_sk(sk)->udp_portaddr_hash accesses. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net> 
ip6_datagram_connect() is doing a lot of socket changes without
socket being locked.

This looks wrong, at least for udp_lib_rehash() which could corrupt
lists because of concurrent udp_sk(sk)->udp_portaddr_hash accesses.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>