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  1. 18 9月, 2015 4 次提交
    • A
      bpf: add bpf_redirect() helper · 27b29f63
      由 Alexei Starovoitov 提交于 
      Existing bpf_clone_redirect() helper clones skb before redirecting
it to RX or TX of destination netdev.
Introduce bpf_redirect() helper that does that without cloning.

Benchmarked with two hosts using 10G ixgbe NICs.
One host is doing line rate pktgen.
Another host is configured as:
$ tc qdisc add dev $dev ingress
$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
   action bpf run object-file tcbpf1_kern.o section clone_redirect_xmit drop
so it receives the packet on $dev and immediately xmits it on $dev + 1
The section 'clone_redirect_xmit' in tcbpf1_kern.o file has the program
that does bpf_clone_redirect() and performance is 2.0 Mpps

$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
   action bpf run object-file tcbpf1_kern.o section redirect_xmit drop
which is using bpf_redirect() - 2.4 Mpps

and using cls_bpf with integrated actions as:
$ tc filter add dev $dev root pref 10 \
  bpf run object-file tcbpf1_kern.o section redirect_xmit integ_act classid 1
performance is 2.5 Mpps

To summarize:
u32+act_bpf using clone_redirect - 2.0 Mpps
u32+act_bpf using redirect - 2.4 Mpps
cls_bpf using redirect - 2.5 Mpps

For comparison linux bridge in this setup is doing 2.1 Mpps
and ixgbe rx + drop in ip_rcv - 7.8 Mpps
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      27b29f63
    • E
      netfilter: Pass net into okfn · 0c4b51f0
      由 Eric W. Biederman 提交于 
      This is immediately motivated by the bridge code that chains functions that
call into netfilter.  Without passing net into the okfns the bridge code would
need to guess about the best expression for the network namespace to process
packets in.

As net is frequently one of the first things computed in continuation functions
after netfilter has done it's job passing in the desired network namespace is in
many cases a code simplification.

To support this change the function dst_output_okfn is introduced to
simplify passing dst_output as an okfn.  For the moment dst_output_okfn
just silently drops the struct net.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      0c4b51f0
    • E
      bridge: Add br_netif_receive_skb remove netif_receive_skb_sk · 04eb4489
      由 Eric W. Biederman 提交于 
      netif_receive_skb_sk is only called once in the bridge code, replace
it with a bridge specific function that calls netif_receive_skb.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      04eb4489
    • E
      net: Remove dev_queue_xmit_sk · 2b4aa3ce
      由 Eric W. Biederman 提交于 
      A function with weird arguments that it will never use to accomdate a
netfilter callback prototype is absolutely in the core of the
networking stack.  Frankly it does not make sense and it causes a lot
of confusion as to why arguments that are never used are being passed
to the function.

As I am preparing to make a second change to arguments to the okfn even
the names stops making sense.

As I have removed the two callers of this function remove this confusion
from the networking stack.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      2b4aa3ce
  3. 31 8月, 2015 1 次提交
  5. 28 8月, 2015 3 次提交
  7. 19 8月, 2015 1 次提交
    • P
      net: warn if drivers set tx_queue_len = 0 · 906470c1
      由 Phil Sutter 提交于 
      Due to the introduction of IFF_NO_QUEUE, there is a better way for
drivers to indicate that no qdisc should be attached by default. Though,
the old convention can't be dropped since ignoring that setting would
break drivers still using it. Instead, add a warning so out-of-tree
driver maintainers get a chance to adjust their code before we finally
get rid of any special handling of tx_queue_len == 0.
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      906470c1
  9. 27 7月, 2015 1 次提交
  11. 22 7月, 2015 1 次提交
    • T
      dst: Metadata destinations · f38a9eb1
      由 Thomas Graf 提交于 
      Introduces a new dst_metadata which enables to carry per packet metadata
between forwarding and processing elements via the skb->dst pointer.

The structure is set up to be a union. Thus, each separate type of
metadata requires its own dst instance. If demand arises to carry
multiple types of metadata concurrently, metadata dst entries can be
made stackable.

The metadata dst entry is refcnt'ed as expected for now but a non
reference counted use is possible if the reference is forced before
queueing the skb.

In order to allow allocating dsts with variable length, the existing
dst_alloc() is split into a dst_alloc() and dst_init() function. The
existing dst_init() function to initialize the subsystem is being
renamed to dst_subsys_init() to make it clear what is what.

The check before ip_route_input() is changed to ignore metadata dsts
and drop the dst inside the routing function thus allowing to interpret
metadata in a later commit.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f38a9eb1
  13. 21 7月, 2015 1 次提交
  15. 16 7月, 2015 1 次提交
  17. 11 7月, 2015 2 次提交
    • J
      net: call rcu_read_lock early in process_backlog · 2c17d27c
      由 Julian Anastasov 提交于 
      Incoming packet should be either in backlog queue or
in RCU read-side section. Otherwise, the final sequence of
flush_backlog() and synchronize_net() may miss packets
that can run without device reference:

CPU 1                  CPU 2
                       skb->dev: no reference
                       process_backlog:__skb_dequeue
                       process_backlog:local_irq_enable

on_each_cpu for
flush_backlog =>       IPI(hardirq): flush_backlog
                       - packet not found in backlog

                       CPU delayed ...
synchronize_net
- no ongoing RCU
read-side sections

netdev_run_todo,
rcu_barrier: no
ongoing callbacks
                       __netif_receive_skb_core:rcu_read_lock
                       - too late
free dev
                       process packet for freed dev

Fixes: 6e583ce5 ("net: eliminate refcounting in backlog queue")
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      2c17d27c
    • J
      net: do not process device backlog during unregistration · e9e4dd32
      由 Julian Anastasov 提交于 
      commit 381c759d ("ipv4: Avoid crashing in ip_error")
fixes a problem where processed packet comes from device
with destroyed inetdev (dev->ip_ptr). This is not expected
because inetdev_destroy is called in NETDEV_UNREGISTER
phase and packets should not be processed after
dev_close_many() and synchronize_net(). Above fix is still
required because inetdev_destroy can be called for other
reasons. But it shows the real problem: backlog can keep
packets for long time and they do not hold reference to
device. Such packets are then delivered to upper levels
at the same time when device is unregistered.
Calling flush_backlog after NETDEV_UNREGISTER_FINAL still
accounts all packets from backlog but before that some packets
continue to be delivered to upper levels long after the
synchronize_net call which is supposed to wait the last
ones. Also, as Eric pointed out, processed packets, mostly
from other devices, can continue to add new packets to backlog.

Fix the problem by moving flush_backlog early, after the
device driver is stopped and before the synchronize_net() call.
Then use netif_running check to make sure we do not add more
packets to backlog. We have to do it in enqueue_to_backlog
context when the local IRQ is disabled. As result, after the
flush_backlog and synchronize_net sequence all packets
should be accounted.

Thanks to Eric W. Biederman for the test script and his
valuable feedback!
Reported-by: NVittorio Gambaletta <linuxbugs@vittgam.net>
Fixes: 6e583ce5 ("net: eliminate refcounting in backlog queue")
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e9e4dd32
  19. 09 7月, 2015 3 次提交
  21. 09 6月, 2015 1 次提交
  23. 02 6月, 2015 1 次提交
  25. 22 5月, 2015 1 次提交
  27. 15 5月, 2015 1 次提交
    • F
      net: core: set qdisc pkt len before tc_classify · 3365495c
      由 Florian Westphal 提交于 
      commit d2788d34 ("net: sched: further simplify handle_ing")
removed the call to qdisc_enqueue_root().

However, after this removal we no longer set qdisc pkt length.
This breaks traffic policing on ingress.

This is the minimum fix: set qdisc pkt length before tc_classify.

Only setting the length does remove support for 'stab' on ingress, but
as Alexei pointed out:
 "Though it was allowed to add qdisc_size_table to ingress, it's useless.
  Nothing takes advantage of recomputed qdisc_pkt_len".

Jamal suggested to use qdisc_pkt_len_init(), but as Eric mentioned that
would result in qdisc_pkt_len_init to no longer get inlined due to the
additional 2nd call site.

ingress policing is rare and GRO doesn't really work that well with police
on ingress, as we see packets > mtu and drop skbs that  -- without
aggregation -- would still have fitted the policier budget.
Thus to have reliable/smooth ingress policing GRO has to be turned off.

Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Fixes: d2788d34 ("net: sched: further simplify handle_ing")
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3365495c
  29. 14 5月, 2015 4 次提交
    • P
      netfilter: add netfilter ingress hook after handle_ing() under unique static key · e687ad60
      由 Pablo Neira 提交于 
      This patch adds the Netfilter ingress hook just after the existing tc ingress
hook, that seems to be the consensus solution for this.

Note that the Netfilter hook resides under the global static key that enables
ingress filtering. Nonetheless, Netfilter still also has its own static key for
minimal impact on the existing handle_ing().

* Without this patch:

Result: OK: 6216490(c6216338+d152) usec, 100000000 (60byte,0frags)
  16086246pps 7721Mb/sec (7721398080bps) errors: 100000000

    42.46%  kpktgend_0   [kernel.kallsyms]   [k] __netif_receive_skb_core
    25.92%  kpktgend_0   [kernel.kallsyms]   [k] kfree_skb
     7.81%  kpktgend_0   [pktgen]            [k] pktgen_thread_worker
     5.62%  kpktgend_0   [kernel.kallsyms]   [k] ip_rcv
     2.70%  kpktgend_0   [kernel.kallsyms]   [k] netif_receive_skb_internal
     2.34%  kpktgend_0   [kernel.kallsyms]   [k] netif_receive_skb_sk
     1.44%  kpktgend_0   [kernel.kallsyms]   [k] __build_skb

* With this patch:

Result: OK: 6214833(c6214731+d101) usec, 100000000 (60byte,0frags)
  16090536pps 7723Mb/sec (7723457280bps) errors: 100000000

    41.23%  kpktgend_0      [kernel.kallsyms]  [k] __netif_receive_skb_core
    26.57%  kpktgend_0      [kernel.kallsyms]  [k] kfree_skb
     7.72%  kpktgend_0      [pktgen]           [k] pktgen_thread_worker
     5.55%  kpktgend_0      [kernel.kallsyms]  [k] ip_rcv
     2.78%  kpktgend_0      [kernel.kallsyms]  [k] netif_receive_skb_internal
     2.06%  kpktgend_0      [kernel.kallsyms]  [k] netif_receive_skb_sk
     1.43%  kpktgend_0      [kernel.kallsyms]  [k] __build_skb

* Without this patch + tc ingress:

        tc filter add dev eth4 parent ffff: protocol ip prio 1 \
                u32 match ip dst 4.3.2.1/32

Result: OK: 9269001(c9268821+d179) usec, 100000000 (60byte,0frags)
  10788648pps 5178Mb/sec (5178551040bps) errors: 100000000

    40.99%  kpktgend_0   [kernel.kallsyms]  [k] __netif_receive_skb_core
    17.50%  kpktgend_0   [kernel.kallsyms]  [k] kfree_skb
    11.77%  kpktgend_0   [cls_u32]          [k] u32_classify
     5.62%  kpktgend_0   [kernel.kallsyms]  [k] tc_classify_compat
     5.18%  kpktgend_0   [pktgen]           [k] pktgen_thread_worker
     3.23%  kpktgend_0   [kernel.kallsyms]  [k] tc_classify
     2.97%  kpktgend_0   [kernel.kallsyms]  [k] ip_rcv
     1.83%  kpktgend_0   [kernel.kallsyms]  [k] netif_receive_skb_internal
     1.50%  kpktgend_0   [kernel.kallsyms]  [k] netif_receive_skb_sk
     0.99%  kpktgend_0   [kernel.kallsyms]  [k] __build_skb

* With this patch + tc ingress:

        tc filter add dev eth4 parent ffff: protocol ip prio 1 \
                u32 match ip dst 4.3.2.1/32

Result: OK: 9308218(c9308091+d126) usec, 100000000 (60byte,0frags)
  10743194pps 5156Mb/sec (5156733120bps) errors: 100000000

    42.01%  kpktgend_0   [kernel.kallsyms]   [k] __netif_receive_skb_core
    17.78%  kpktgend_0   [kernel.kallsyms]   [k] kfree_skb
    11.70%  kpktgend_0   [cls_u32]           [k] u32_classify
     5.46%  kpktgend_0   [kernel.kallsyms]   [k] tc_classify_compat
     5.16%  kpktgend_0   [pktgen]            [k] pktgen_thread_worker
     2.98%  kpktgend_0   [kernel.kallsyms]   [k] ip_rcv
     2.84%  kpktgend_0   [kernel.kallsyms]   [k] tc_classify
     1.96%  kpktgend_0   [kernel.kallsyms]   [k] netif_receive_skb_internal
     1.57%  kpktgend_0   [kernel.kallsyms]   [k] netif_receive_skb_sk

Note that the results are very similar before and after.

I can see gcc gets the code under the ingress static key out of the hot path.
Then, on that cold branch, it generates the code to accomodate the netfilter
ingress static key. My explanation for this is that this reduces the pressure
on the instruction cache for non-users as the new code is out of the hot path,
and it comes with minimal impact for tc ingress users.

Using gcc version 4.8.4 on:

Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
[...]
L1d cache:             16K
L1i cache:             64K
L2 cache:              2048K
L3 cache:              8192K
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e687ad60
    • P
      net: add CONFIG_NET_INGRESS to enable ingress filtering · 1cf51900
      由 Pablo Neira 提交于 
      This new config switch enables the ingress filtering infrastructure that is
controlled through the ingress_needed static key. This prepares the
introduction of the Netfilter ingress hook that resides under this unique
static key.

Note that CONFIG_SCH_INGRESS automatically selects this, that should be no
problem since this also depends on CONFIG_NET_CLS_ACT.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1cf51900
    • J
      net: move netdev_pick_tx and dependencies to net/core/dev.c · 638b2a69
      由 Jiri Pirko 提交于 
      next to its user. No relation to flow_dissector so it makes no sense to
have it in flow_dissector.c
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      638b2a69
    • J
      net: move __skb_tx_hash to dev.c · 5605c762
      由 Jiri Pirko 提交于 
      __skb_tx_hash function has no relation to flow_dissect so just move it
to dev.c
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      5605c762
  31. 13 5月, 2015 1 次提交
    • D
      net: deinline netif_tx_stop_all_queues(), remove WARN_ON in netif_tx_stop_queue() · a2029240
      由 Denys Vlasenko 提交于 
      These functions compile to 60 bytes of machine code each.
With this .config: http://busybox.net/~vda/kernel_config
there are 617 calls of netif_tx_stop_queue()
and 49 calls of netif_tx_stop_all_queues() in vmlinux.

To fix this, remove WARN_ON in netif_tx_stop_queue()
as suggested by davem, and deinline netif_tx_stop_all_queues().

Change in code size is about 20k:

   text      data      bss       dec     hex filename
82426986 22255416 20627456 125309858 77813a2 vmlinux.before
82406248 22255416 20627456 125289120 777c2a0 vmlinux

gcc-4.7.2 still creates deinlined version of netif_tx_stop_queue
sometimes:

$ nm --size-sort vmlinux | grep netif_tx_stop_queue | wc -l
190

ffffffff81b558a8 <netif_tx_stop_queue>:
ffffffff81b558a8:       55                      push   %rbp
ffffffff81b558a9:       48 89 e5                mov    %rsp,%rbp
ffffffff81b558ac:       f0 80 8f e0 01 00 00    lock orb $0x1,0x1e0(%rdi)
ffffffff81b558b3:       01
ffffffff81b558b4:       5d                      pop    %rbp
ffffffff81b558b5:       c3                      retq

This needs additional fixing.
Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com>
CC: Alexei Starovoitov <alexei.starovoitov@gmail.com>
CC: Alexander Duyck <alexander.duyck@gmail.com>
CC: Joe Perches <joe@perches.com>
CC: David S. Miller <davem@davemloft.net>
CC: Jiri Pirko <jpirko@redhat.com>
CC: linux-kernel@vger.kernel.org
CC: netdev@vger.kernel.org
CC: netfilter-devel@vger.kernel.org
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a2029240
  33. 11 5月, 2015 2 次提交
    • D
      net: sched: further simplify handle_ing · d2788d34
      由 Daniel Borkmann 提交于 
      Ingress qdisc has no other purpose than calling into tc_classify()
that executes attached classifier(s) and action(s).

It has a 1:1 relationship to dev->ingress_queue. After having commit
087c1a60 ("net: sched: run ingress qdisc without locks") removed
the central ingress lock, one major contention point is gone.

The extra indirection layers however, are not necessary for calling
into ingress qdisc. pktgen calling locally into netif_receive_skb()
with a dummy u32, single CPU result on a Supermicro X10SLM-F, Xeon
E3-1240: before ~21,1 Mpps, after patch ~22,9 Mpps.

We can redirect the private classifier list to the netdev directly,
without changing any classifier API bits (!) and execute on that from
handle_ing() side. The __QDISC_STATE_DEACTIVATE test can be removed,
ingress qdisc doesn't have a queue and thus dev_deactivate_queue()
is also not applicable, ingress_cl_list provides similar behaviour.
In other words, ingress qdisc acts like TCQ_F_BUILTIN qdisc.

One next possible step is the removal of the dev's ingress (dummy)
netdev_queue, and to only have the list member in the netdevice
itself.

Note, the filter chain is RCU protected and individual filter elements
are being kfree'd by sched subsystem after RCU grace period. RCU read
lock is being held by __netif_receive_skb_core().

Joint work with Alexei Starovoitov.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d2788d34
    • D
      net: sched: consolidate handle_ing and ing_filter · c9e99fd0
      由 Daniel Borkmann 提交于 
      Given quite some code has been removed from ing_filter(), we can just
consolidate that function into handle_ing() and get rid of a few
instructions at the same time.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      c9e99fd0
  35. 05 5月, 2015 2 次提交
  37. 04 5月, 2015 1 次提交
  39. 27 4月, 2015 1 次提交
    • E
      net: rfs: fix crash in get_rps_cpus() · a31196b0
      由 Eric Dumazet 提交于 
      Commit 567e4b79 ("net: rfs: add hash collision detection") had one
mistake :

RPS_NO_CPU is no longer the marker for invalid cpu in set_rps_cpu()
and get_rps_cpu(), as @next_cpu was the result of an AND with
rps_cpu_mask

This bug showed up on a host with 72 cpus :
next_cpu was 0x7f, and the code was trying to access percpu data of an
non existent cpu.

In a follow up patch, we might get rid of compares against nr_cpu_ids,
if we init the tables with 0. This is silly to test for a very unlikely
condition that exists only shortly after table initialization, as
we got rid of rps_reset_sock_flow() and similar functions that were
writing this RPS_NO_CPU magic value at flow dismantle : When table is
old enough, it never contains this value anymore.

Fixes: 567e4b79 ("net: rfs: add hash collision detection")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a31196b0
  41. 18 4月, 2015 1 次提交
  43. 14 4月, 2015 1 次提交
    • D
      net: use jump label patching for ingress qdisc in __netif_receive_skb_core · 4577139b
      由 Daniel Borkmann 提交于 
      Even if we make use of classifier and actions from the egress
path, we're going into handle_ing() executing additional code
on a per-packet cost for ingress qdisc, just to realize that
nothing is attached on ingress.

Instead, this can just be blinded out as a no-op entirely with
the use of a static key. On input fast-path, we already make
use of static keys in various places, e.g. skb time stamping,
in RPS, etc. It makes sense to not waste time when we're assured
that no ingress qdisc is attached anywhere.

Enabling/disabling of that code path is being done via two
helpers, namely net_{inc,dec}_ingress_queue(), that are being
invoked under RTNL mutex when a ingress qdisc is being either
initialized or destructed.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4577139b
  45. 08 4月, 2015 1 次提交
    • D
      netfilter: Pass socket pointer down through okfn(). · 7026b1dd
      由 David Miller 提交于 
      On the output paths in particular, we have to sometimes deal with two
socket contexts.  First, and usually skb->sk, is the local socket that
generated the frame.

And second, is potentially the socket used to control a tunneling
socket, such as one the encapsulates using UDP.

We do not want to disassociate skb->sk when encapsulating in order
to fix this, because that would break socket memory accounting.

The most extreme case where this can cause huge problems is an
AF_PACKET socket transmitting over a vxlan device.  We hit code
paths doing checks that assume they are dealing with an ipv4
socket, but are actually operating upon the AF_PACKET one.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7026b1dd
  47. 07 4月, 2015 1 次提交
    • H
      ipv6: protect skb->sk accesses from recursive dereference inside the stack · f60e5990
      由 hannes@stressinduktion.org 提交于 
      We should not consult skb->sk for output decisions in xmit recursion
levels > 0 in the stack. Otherwise local socket settings could influence
the result of e.g. tunnel encapsulation process.

ipv6 does not conform with this in three places:

1) ip6_fragment: we do consult ipv6_npinfo for frag_size

2) sk_mc_loop in ipv6 uses skb->sk and checks if we should
   loop the packet back to the local socket

3) ip6_skb_dst_mtu could query the settings from the user socket and
   force a wrong MTU

Furthermore:
In sk_mc_loop we could potentially land in WARN_ON(1) if we use a
PF_PACKET socket ontop of an IPv6-backed vxlan device.

Reuse xmit_recursion as we are currently only interested in protecting
tunnel devices.

Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f60e5990
  49. 03 4月, 2015 3 次提交