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  1. 14 1月, 2017 1 次提交
    • Y
      tcp: remove thin_dupack feature · 4a7f6009
      由 Yuchung Cheng 提交于 
      Thin stream DUPACK is to start fast recovery on only one DUPACK
provided the connection is a thin stream (i.e., low inflight).  But
this older feature is now subsumed with RACK. If a connection
receives only a single DUPACK, RACK would arm a reordering timer
and soon starts fast recovery instead of timeout if no further
ACKs are received.

The socket option (THIN_DUPACK) is kept as a nop for compatibility.
Note that this patch does not change another thin-stream feature
which enables linear RTO. Although it might be good to generalize
that in the future (i.e., linear RTO for the first say 3 retries).
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4a7f6009
  3. 10 1月, 2017 1 次提交
  5. 30 12月, 2016 2 次提交
  7. 28 12月, 2016 1 次提交
  9. 23 10月, 2016 1 次提交
    • W
      ipv4: use the right lock for ping_group_range · 396a30cc
      由 WANG Cong 提交于 
      This reverts commit a681574c
("ipv4: disable BH in set_ping_group_range()") because we never
read ping_group_range in BH context (unlike local_port_range).

Then, since we already have a lock for ping_group_range, those
using ip_local_ports.lock for ping_group_range are clearly typos.

We might consider to share a same lock for both ping_group_range
and local_port_range w.r.t. space saving, but that should be for
net-next.

Fixes: a681574c ("ipv4: disable BH in set_ping_group_range()")
Fixes: ba6b918a ("ping: move ping_group_range out of CONFIG_SYSCTL")
Cc: Eric Dumazet <edumazet@google.com>
Cc: Eric Salo <salo@google.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      396a30cc
  11. 21 10月, 2016 1 次提交
  13. 24 5月, 2016 1 次提交
    • E
      ipv4: Fix non-initialized TTL when CONFIG_SYSCTL=n · 049bbf58
      由 Ezequiel Garcia 提交于 
      Commit fa50d974 ("ipv4: Namespaceify ip_default_ttl sysctl knob")
moves the default TTL assignment, and as side-effect IPv4 TTL now
has a default value only if sysctl support is enabled (CONFIG_SYSCTL=y).

The sysctl_ip_default_ttl is fundamental for IP to work properly,
as it provides the TTL to be used as default. The defautl TTL may be
used in ip_selected_ttl, through the following flow:

  ip_select_ttl
    ip4_dst_hoplimit
      net->ipv4.sysctl_ip_default_ttl

This commit fixes the issue by assigning net->ipv4.sysctl_ip_default_ttl
in net_init_net, called during ipv4's initialization.

Without this commit, a kernel built without sysctl support will send
all IP packets with zero TTL (unless a TTL is explicitly set, e.g.
with setsockopt).

Given a similar issue might appear on the other knobs that were
namespaceify, this commit also moves them.

Fixes: fa50d974 ("ipv4: Namespaceify ip_default_ttl sysctl knob")
Signed-off-by: NEzequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      049bbf58
  15. 12 4月, 2016 1 次提交
    • D
      net: ipv4: Consider failed nexthops in multipath routes · a6db4494
      由 David Ahern 提交于 
      Multipath route lookups should consider knowledge about next hops and not
select a hop that is known to be failed.

Example:

                     [h2]                   [h3]   15.0.0.5
                      |                      |
                     3|                     3|
                    [SP1]                  [SP2]--+
                     1  2                   1     2
                     |  |     /-------------+     |
                     |   \   /                    |
                     |     X                      |
                     |    / \                     |
                     |   /   \---------------\    |
                     1  2                     1   2
         12.0.0.2  [TOR1] 3-----------------3 [TOR2] 12.0.0.3
                     4                         4
                      \                       /
                        \                    /
                         \                  /
                          -------|   |-----/
                                 1   2
                                [TOR3]
                                  3|
                                   |
                                  [h1]  12.0.0.1

host h1 with IP 12.0.0.1 has 2 paths to host h3 at 15.0.0.5:

    root@h1:~# ip ro ls
    ...
    12.0.0.0/24 dev swp1  proto kernel  scope link  src 12.0.0.1
    15.0.0.0/16
            nexthop via 12.0.0.2  dev swp1 weight 1
            nexthop via 12.0.0.3  dev swp1 weight 1
    ...

If the link between tor3 and tor1 is down and the link between tor1
and tor2 then tor1 is effectively cut-off from h1. Yet the route lookups
in h1 are alternating between the 2 routes: ping 15.0.0.5 gets one and
ssh 15.0.0.5 gets the other. Connections that attempt to use the
12.0.0.2 nexthop fail since that neighbor is not reachable:

    root@h1:~# ip neigh show
    ...
    12.0.0.3 dev swp1 lladdr 00:02:00:00:00:1b REACHABLE
    12.0.0.2 dev swp1  FAILED
    ...

The failed path can be avoided by considering known neighbor information
when selecting next hops. If the neighbor lookup fails we have no
knowledge about the nexthop, so give it a shot. If there is an entry
then only select the nexthop if the state is sane. This is similar to
what fib_detect_death does.

To maintain backward compatibility use of the neighbor information is
based on a new sysctl, fib_multipath_use_neigh.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Reviewed-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a6db4494
  17. 17 2月, 2016 3 次提交
  19. 11 2月, 2016 4 次提交
  21. 08 2月, 2016 9 次提交
  23. 21 1月, 2016 1 次提交
  25. 11 1月, 2016 3 次提交
  27. 19 12月, 2015 1 次提交
    • D
      net: Allow accepted sockets to be bound to l3mdev domain · 6dd9a14e
      由 David Ahern 提交于 
      Allow accepted sockets to derive their sk_bound_dev_if setting from the
l3mdev domain in which the packets originated. A sysctl setting is added
to control the behavior which is similar to sk_mark and
sysctl_tcp_fwmark_accept.

This effectively allow a process to have a "VRF-global" listen socket,
with child sockets bound to the VRF device in which the packet originated.
A similar behavior can be achieved using sk_mark, but a solution using marks
is incomplete as it does not handle duplicate addresses in different L3
domains/VRFs. Allowing sockets to inherit the sk_bound_dev_if from l3mdev
domain provides a complete solution.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6dd9a14e
  29. 05 11月, 2015 1 次提交
    • W
      ipv4: disable BH when changing ip local port range · 4ee3bd4a
      由 WANG Cong 提交于 
      This fixes the following lockdep warning:

 [ INFO: inconsistent lock state ]
 4.3.0-rc7+ #1197 Not tainted
 ---------------------------------
 inconsistent {IN-SOFTIRQ-R} -> {SOFTIRQ-ON-W} usage.
 sysctl/1019 [HC0[0]:SC0[0]:HE1:SE1] takes:
  (&(&net->ipv4.ip_local_ports.lock)->seqcount){+.+-..}, at: [<ffffffff81921de7>] ipv4_local_port_range+0xb4/0x12a
 {IN-SOFTIRQ-R} state was registered at:
   [<ffffffff810bd682>] __lock_acquire+0x2f6/0xdf0
   [<ffffffff810be6d5>] lock_acquire+0x11c/0x1a4
   [<ffffffff818e599c>] inet_get_local_port_range+0x4e/0xae
   [<ffffffff8166e8e3>] udp_flow_src_port.constprop.40+0x23/0x116
   [<ffffffff81671cb9>] vxlan_xmit_one+0x219/0xa6a
   [<ffffffff81672f75>] vxlan_xmit+0xa6b/0xaa5
   [<ffffffff817f2deb>] dev_hard_start_xmit+0x2ae/0x465
   [<ffffffff817f35ed>] __dev_queue_xmit+0x531/0x633
   [<ffffffff817f3702>] dev_queue_xmit_sk+0x13/0x15
   [<ffffffff818004a5>] neigh_resolve_output+0x12f/0x14d
   [<ffffffff81959cfa>] ip6_finish_output2+0x344/0x39f
   [<ffffffff8195bf58>] ip6_finish_output+0x88/0x8e
   [<ffffffff8195bfef>] ip6_output+0x91/0xe5
   [<ffffffff819792ae>] dst_output_sk+0x47/0x4c
   [<ffffffff81979392>] NF_HOOK_THRESH.constprop.30+0x38/0x82
   [<ffffffff8197981e>] mld_sendpack+0x189/0x266
   [<ffffffff8197b28b>] mld_ifc_timer_expire+0x1ef/0x223
   [<ffffffff810de581>] call_timer_fn+0xfb/0x28c
   [<ffffffff810ded1e>] run_timer_softirq+0x1c7/0x1f1

Fixes: b8f1a556 ("udp: Add function to make source port for UDP tunnels")
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4ee3bd4a
  31. 21 10月, 2015 2 次提交
    • Y
      tcp: use RACK to detect losses · 4f41b1c5
      由 Yuchung Cheng 提交于 
      This patch implements the second half of RACK that uses the the most
recent transmit time among all delivered packets to detect losses.

tcp_rack_mark_lost() is called upon receiving a dubious ACK.
It then checks if an not-yet-sacked packet was sent at least
"reo_wnd" prior to the sent time of the most recently delivered.
If so the packet is deemed lost.

The "reo_wnd" reordering window starts with 1msec for fast loss
detection and changes to min-RTT/4 when reordering is observed.
We found 1msec accommodates well on tiny degree of reordering
(<3 pkts) on faster links. We use min-RTT instead of SRTT because
reordering is more of a path property but SRTT can be inflated by
self-inflicated congestion. The factor of 4 is borrowed from the
delayed early retransmit and seems to work reasonably well.

Since RACK is still experimental, it is now used as a supplemental
loss detection on top of existing algorithms. It is only effective
after the fast recovery starts or after the timeout occurs. The
fast recovery is still triggered by FACK and/or dupack threshold
instead of RACK.

We introduce a new sysctl net.ipv4.tcp_recovery for future
experiments of loss recoveries. For now RACK can be disabled by
setting it to 0.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4f41b1c5
    • Y
      tcp: track min RTT using windowed min-filter · f6722583
      由 Yuchung Cheng 提交于 
      Kathleen Nichols' algorithm for tracking the minimum RTT of a
data stream over some measurement window. It uses constant space
and constant time per update. Yet it almost always delivers
the same minimum as an implementation that has to keep all
the data in the window. The measurement window is tunable via
sysctl.net.ipv4.tcp_min_rtt_wlen with a default value of 5 minutes.

The algorithm keeps track of the best, 2nd best & 3rd best min
values, maintaining an invariant that the measurement time of
the n'th best >= n-1'th best. It also makes sure that the three
values are widely separated in the time window since that bounds
the worse case error when that data is monotonically increasing
over the window.

Upon getting a new min, we can forget everything earlier because
it has no value - the new min is less than everything else in the
window by definition and it's the most recent. So we restart fresh
on every new min and overwrites the 2nd & 3rd choices. The same
property holds for the 2nd & 3rd best.

Therefore we have to maintain two invariants to maximize the
information in the samples, one on values (1st.v <= 2nd.v <=
3rd.v) and the other on times (now-win <=1st.t <= 2nd.t <= 3rd.t <=
now). These invariants determine the structure of the code

The RTT input to the windowed filter is the minimum RTT measured
from ACK or SACK, or as the last resort from TCP timestamps.

The accessor tcp_min_rtt() returns the minimum RTT seen in the
window. ~0U indicates it is not available. The minimum is 1usec
even if the true RTT is below that.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f6722583
  33. 14 10月, 2015 1 次提交
  35. 13 10月, 2015 1 次提交
    • P
      ipv4/icmp: redirect messages can use the ingress daddr as source · e2ca690b
      由 Paolo Abeni 提交于 
      This patch allows configuring how the source address of ICMP
redirect messages is selected; by default the old behaviour is
retained, while setting icmp_redirects_use_orig_daddr force the
usage of the destination address of the packet that caused the
redirect.

The new behaviour fits closely the RFC 5798 section 8.1.1, and fix the
following scenario:

Two machines are set up with VRRP to act as routers out of a subnet,
they have IPs x.x.x.1/24 and x.x.x.2/24, with VRRP holding on to
x.x.x.254/24.

If a host in said subnet needs to get an ICMP redirect from the VRRP
router, i.e. to reach a destination behind a different gateway, the
source IP in the ICMP redirect is chosen as the primary IP on the
interface that the packet arrived at, i.e. x.x.x.1 or x.x.x.2.

The host will then ignore said redirect, due to RFC 1122 section 3.2.2.2,
and will continue to use the wrong next-op.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e2ca690b
  37. 29 8月, 2015 1 次提交
    • P
      IGMP: Inhibit reports for local multicast groups · df2cf4a7
      由 Philip Downey 提交于 
      The range of addresses between 224.0.0.0 and 224.0.0.255 inclusive, is
reserved for the use of routing protocols and other low-level topology
discovery or maintenance protocols, such as gateway discovery and
group membership reporting.  Multicast routers should not forward any
multicast datagram with destination addresses in this range,
regardless of its TTL.

Currently, IGMP reports are generated for this reserved range of
addresses even though a router will ignore this information since it
has no purpose.  However, the presence of reserved group addresses in
an IGMP membership report uses up network bandwidth and can also
obscure addresses of interest when inspecting membership reports using
packet inspection or debug messages.

Although the RFCs for the various version of IGMP (e.g.RFC 3376 for
v3) do not specify that the reserved addresses be excluded from
membership reports, it should do no harm in doing so.  In particular
there should be no adverse effect in any IGMP snooping functionality
since 224.0.0.x is specifically excluded as per RFC 4541 (IGMP and MLD
Snooping Switches Considerations) section 2.1.2. Data Forwarding
Rules:

    2) Packets with a destination IP (DIP) address in the 224.0.0.X
       range which are not IGMP must be forwarded on all ports.

IGMP reports for local multicast groups can now be optionally
inhibited by means of a system control variable (by setting the value
to zero) e.g.:
    echo 0 > /proc/sys/net/ipv4/igmp_link_local_mcast_reports

To retain backwards compatibility the previous behaviour is retained
by default on system boot or reverted by setting the value back to
non-zero e.g.:
    echo 1 >  /proc/sys/net/ipv4/igmp_link_local_mcast_reports
Signed-off-by: NPhilip Downey <pdowney@brocade.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      df2cf4a7
  39. 26 8月, 2015 1 次提交
    • E
      tcp: refine pacing rate determination · 43e122b0
      由 Eric Dumazet 提交于 
      When TCP pacing was added back in linux-3.12, we chose
to apply a fixed ratio of 200 % against current rate,
to allow probing for optimal throughput even during
slow start phase, where cwnd can be doubled every other gRTT.

At Google, we found it was better applying a different ratio
while in Congestion Avoidance phase.
This ratio was set to 120 %.

We've used the normal tcp_in_slow_start() helper for a while,
then tuned the condition to select the conservative ratio
as soon as cwnd >= ssthresh/2 :

- After cwnd reduction, it is safer to ramp up more slowly,
  as we approach optimal cwnd.
- Initial ramp up (ssthresh == INFINITY) still allows doubling
  cwnd every other RTT.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      43e122b0
  41. 18 8月, 2015 1 次提交
    • C
      Revert "net: limit tcp/udp rmem/wmem to SOCK_{RCV,SND}BUF_MIN" · 5d37852b
      由 Calvin Owens 提交于 
      Commit 8133534c ("net: limit tcp/udp rmem/wmem to
SOCK_{RCV,SND}BUF_MIN") modified four sysctls to enforce that the values
written to them are not less than SOCK_MIN_{RCV,SND}BUF.

That change causes 4096 to no longer be accepted as a valid value for
'min' in tcp_wmem and udp_wmem_min. 4096 has been the default for both
of those sysctls for a long time, and unfortunately seems to be an
extremely popular setting. This change breaks a large number of sysctl
configurations at Facebook.

That commit referred to b1cb59cf ("net: sysctl_net_core: check
SNDBUF and RCVBUF for min length"), which choose to use the SOCK_MIN
constants as the lower limits to avoid nasty bugs. But AFAICS, a limit
of SOCK_MIN_SNDBUF isn't necessary to do that: the BUG_ON cited in the
commit message seems to have happened because unix_stream_sendmsg()
expects a minimum of a full page (ie SK_MEM_QUANTUM) and the math broke,
not because it had less than SOCK_MIN_SNDBUF allocated.

This particular issue doesn't seem to affect TCP however: using a
setting of "1 1 1" for tcp_{r,w}mem works, although it's obviously
suboptimal. SK_MEM_QUANTUM would be a nice minimum, but it's 64K on
some archs, so there would still be breakage.

Since a value of one doesn't seem to cause any problems, we can drop the
minimum 8133534c added to fix this.

This reverts commit 8133534c.

Fixes: 8133534c ("net: limit tcp/udp rmem/wmem to SOCK_MIN...")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sorin Dumitru <sorin@returnze.ro>
Signed-off-by: NCalvin Owens <calvinowens@fb.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      5d37852b
  43. 31 5月, 2015 1 次提交
  45. 28 5月, 2015 1 次提交