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  1. 07 5月, 2016 8 次提交
    • A
      bpf: add documentation for 'direct packet access' · f9c8d19d
      由 Alexei Starovoitov 提交于 
      explain how verifier checks safety of packet access
and update email addresses.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f9c8d19d
    • A
      bpf: wire in data and data_end for cls_act_bpf · db58ba45
      由 Alexei Starovoitov 提交于 
      allow cls_bpf and act_bpf programs access skb->data and skb->data_end pointers.
The bpf helpers that change skb->data need to update data_end pointer as well.
The verifier checks that programs always reload data, data_end pointers
after calls to such bpf helpers.
We cannot add 'data_end' pointer to struct qdisc_skb_cb directly,
since it's embedded as-is by infiniband ipoib, so wrapper struct is needed.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      db58ba45
    • A
      bpf: improve verifier state equivalence · 735b4333
      由 Alexei Starovoitov 提交于 
      since UNKNOWN_VALUE type is weaker than CONST_IMM we can un-teach
verifier its recognition of constants in conditional branches
without affecting safety.
Ex:
if (reg == 123) {
  .. here verifier was marking reg->type as CONST_IMM
     instead keep reg as UNKNOWN_VALUE
}

Two verifier states with UNKNOWN_VALUE are equivalent, whereas
CONST_IMM_X != CONST_IMM_Y, since CONST_IMM is used for stack range
verification and other cases.
So help search pruning by marking registers as UNKNOWN_VALUE
where possible instead of CONST_IMM.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      735b4333
    • A
      bpf: direct packet access · 969bf05e
      由 Alexei Starovoitov 提交于 
      Extended BPF carried over two instructions from classic to access
packet data: LD_ABS and LD_IND. They're highly optimized in JITs,
but due to their design they have to do length check for every access.
When BPF is processing 20M packets per second single LD_ABS after JIT
is consuming 3% cpu. Hence the need to optimize it further by amortizing
the cost of 'off < skb_headlen' over multiple packet accesses.
One option is to introduce two new eBPF instructions LD_ABS_DW and LD_IND_DW
with similar usage as skb_header_pointer().
The kernel part for interpreter and x64 JIT was implemented in [1], but such
new insns behave like old ld_abs and abort the program with 'return 0' if
access is beyond linear data. Such hidden control flow is hard to workaround
plus changing JITs and rolling out new llvm is incovenient.

Therefore allow cls_bpf/act_bpf program access skb->data directly:
int bpf_prog(struct __sk_buff *skb)
{
  struct iphdr *ip;

  if (skb->data + sizeof(struct iphdr) + ETH_HLEN > skb->data_end)
      /* packet too small */
      return 0;

  ip = skb->data + ETH_HLEN;

  /* access IP header fields with direct loads */
  if (ip->version != 4 || ip->saddr == 0x7f000001)
      return 1;
  [...]
}

This solution avoids introduction of new instructions. llvm stays
the same and all JITs stay the same, but verifier has to work extra hard
to prove safety of the above program.

For XDP the direct store instructions can be allowed as well.

The skb->data is NET_IP_ALIGNED, so for common cases the verifier can check
the alignment. The complex packet parsers where packet pointer is adjusted
incrementally cannot be tracked for alignment, so allow byte access in such cases
and misaligned access on architectures that define efficient_unaligned_access

[1] https://git.kernel.org/cgit/linux/kernel/git/ast/bpf.git/?h=ld_abs_dwSigned-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      969bf05e
    • A
      bpf: cleanup verifier code · 1a0dc1ac
      由 Alexei Starovoitov 提交于 
      cleanup verifier code and prepare it for addition of "pointer to packet" logic
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      1a0dc1ac
    • D
      Merge branch '40GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/jkirsher/next-queue · 95aef7ce
      由 David S. Miller 提交于 
      Jeff Kirsher says:

====================
40GbE Intel Wired LAN Driver Updates 2016-05-05

This series contains updates to i40e and i40evf.

The theme behind this series is code reduction, yeah!  Jesse provides
most of the changes starting with a refactor of the interpretation of
a tunnel which lets us start using the hardware's parsing.  Removed
the packet split receive routine and ancillary code in preparation
for the Rx-refactor.  The refactor of the receive routine,
aligns the receive routine with the one in ixgbe which was highly
optimized.  The hardware supports a 16 byte descriptor for receive,
but the driver was never using it in production.  There was no performance
benefit to the real driver of 16 byte descriptors, so drop a whole lot
of complexity while getting rid of the code.  Fixed a bug where while
changing the number of descriptors using ethtool, the driver did not
test the limits of the system memory before permanently assuming it
would be able to get receive buffer memory.

Mitch fixes a memory leak of one page each time the driver is opened by
allocating the correct number of receive buffers and do not fiddle with
next_to_use in the VF driver.

Arnd Bergmann fixed a indentation issue by adding the appropriate
curly braces in i40e_vc_config_promiscuous_mode_msg().

Julia Lawall fixed an issue found by Coccinelle, where i40e_client_ops
structure can be const since it is never modified.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      95aef7ce
    • D
      net: vrf: Create FIB tables on link create · b3b4663c
      由 David Ahern 提交于 
      Tables have to exist for VRFs to function. Ensure they exist
when VRF device is created.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b3b4663c
    • J
      cnic: call cp->stop_hw() in cnic_start_hw() on allocation failure · f37bd0cc
      由 Jon Maxwell 提交于 
      We recently had a system crash in the cnic module. Vmcore analysis confirmed
that "ip link up" was executed which failed due to an allocation failure
because of memory fragmentation. Futher analysis revealed that the cnic irq
vector was still allocated after the "ip link up" that failed. When
"ip link down" was executed it called free_msi_irqs() which crashed the system
because the cnic irq was still inuse.

PANIC: "kernel BUG at drivers/pci/msi.c:411!"

The code execution was:

cnic_netdev_event()
if (event == NETDEV_UP) {
.
.
       ▹       if (!cnic_start_hw(dev))
cnic_start_hw()
calls cnic_cm_open() which failed with -ENOMEM
cnic_start_hw() then took the err1 path:

err1:↩
       cp->free_resc(dev);↩ <---- frees resources but not irq vector
       pci_dev_put(dev->pcidev);↩
       return err;↩
}↩

This returns control back to cnic_netdev_event() but now the cnic irq vector
is still allocated even although cnic_cm_open() failed. The next
"ip link down" while trigger the crash.

The cnic_start_hw() routine is not handling the allocation failure correctly.
Fix this by checking whether CNIC_DRV_STATE_HANDLES_IRQ flag is set indicating
that the hardware has been started in cnic_start_hw(). If it has then call
cp->stop_hw() which frees the cnic irq vector and cnic resources. Otherwise
just maintain the previous behaviour and free cnic resources.

I reproduced this by injecting an ENOMEM error into cnic_cm_alloc_mem()s return
code.

# ip link set dev enpX down
# ip link set dev enpX up <--- hit's allocation failure
# ip link set dev enpX down <--- crashes here

With this patch I confirmed there was no crash in the reproducer.
Signed-off-by: NJon Maxwell <jmaxwell37@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f37bd0cc
  3. 06 5月, 2016 12 次提交
  5. 05 5月, 2016 20 次提交