linux.git/net/core/dev.c, branch v4.20-rc4

net: don't keep lonely packets forever in the gro hash

2018-11-23T19:18:53+00:00

Eric noted that with UDP GRO and NAPI timeout, we could keep a single
UDP packet inside the GRO hash forever, if the related NAPI instance
calls napi_gro_complete() at an higher frequency than the NAPI timeout.
Willem noted that even TCP packets could be trapped there, till the
next retransmission.
This patch tries to address the issue, flushing the old packets -
those with a NAPI_GRO_CB age before the current jiffy - before scheduling
the NAPI timeout. The rationale is that such a timeout should be
well below a jiffy and we are not flushing packets eligible for sane GRO.

v1  -> v2:
 - clarified the commit message and comment

RFC -> v1:
 - added 'Fixes tags', cleaned-up the wording.

Reported-by: Eric Dumazet 
Fixes: 3b47d30396ba ("net: gro: add a per device gro flush timer")
Signed-off-by: Paolo Abeni 
Acked-by: Willem de Bruijn 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

net-gro: reset skb->pkt_type in napi_reuse_skb()

2018-11-18T05:59:18+00:00

eth_type_trans() assumes initial value for skb->pkt_type
is PACKET_HOST.

This is indeed the value right after a fresh skb allocation.

However, it is possible that GRO merged a packet with a different
value (like PACKET_OTHERHOST in case macvlan is used), so
we need to make sure napi->skb will have pkt_type set back to
PACKET_HOST.

Otherwise, valid packets might be dropped by the stack because
their pkt_type is not PACKET_HOST.

napi_reuse_skb() was added in commit 96e93eab2033 ("gro: Add
internal interfaces for VLAN"), but this bug always has
been there.

Fixes: 96e93eab2033 ("gro: Add internal interfaces for VLAN")
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: do not abort bulk send on BQL status

2018-11-03T22:40:01+00:00

Before calling dev_hard_start_xmit(), upper layers tried
to cook optimal skb list based on BQL budget.

Problem is that GSO packets can end up comsuming more than
the BQL budget.

Breaking the loop is not useful, since requeued packets
are ahead of any packets still in the qdisc.

It is also more expensive, since next TX completion will
push these packets later, while skbs are not in cpu caches.

It is also a behavior difference with TSO packets, that can
break the BQL limit by a large amount.

Note that drivers should use __netdev_tx_sent_queue()
in order to have optimal xmit_more support, and avoid
useless atomic operations as shown in the following patch.

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

net: Properly unlink GRO packets on overflow.

2018-10-28T17:35:12+00:00

Just like with normal GRO processing, we have to initialize
skb->next to NULL when we unlink overflow packets from the
GRO hash lists.

Fixes: d4546c2509b1 ("net: Convert GRO SKB handling to list_head.")
Reported-by: Oleksandr Natalenko 
Tested-by: Oleksandr Natalenko 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2018-10-16T06:21:07+00:00

Daniel Borkmann says:

====================
pull-request: bpf-next 2018-10-16

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Convert BPF sockmap and kTLS to both use a new sk_msg API and enable
   sk_msg BPF integration for the latter, from Daniel and John.

2) Enable BPF syscall side to indicate for maps that they do not support
   a map lookup operation as opposed to just missing key, from Prashant.

3) Add bpftool map create command which after map creation pins the
   map into bpf fs for further processing, from Jakub.

4) Add bpftool support for attaching programs to maps allowing sock_map
   and sock_hash to be used from bpftool, from John.

5) Improve syscall BPF map update/delete path for map-in-map types to
   wait a RCU grace period for pending references to complete, from Daniel.

6) Couple of follow-up fixes for the BPF socket lookup to get it
   enabled also when IPv6 is compiled as a module, from Joe.

7) Fix a generic-XDP bug to handle the case when the Ethernet header
   was mangled and thus update skb's protocol and data, from Jesper.

8) Add a missing BTF header length check between header copies from
   user space, from Wenwen.

9) Minor fixups in libbpf to use __u32 instead u32 types and include
   proper perf_event.h uapi header instead of perf internal one, from Yonghong.

10) Allow to pass user-defined flags through EXTRA_CFLAGS and EXTRA_LDFLAGS
    to bpftool's build, from Jiri.

11) BPF kselftest tweaks to add LWTUNNEL to config fragment and to install
    with_addr.sh script from flow dissector selftest, from Anders.
====================

Signed-off-by: David S. Miller

FDDI: defza: Support capturing outgoing SMT traffic

2018-10-16T04:46:06+00:00

DEC FDDIcontroller 700 (DEFZA) uses a Tx/Rx queue pair to communicate
SMT frames with adapter's firmware.  Any SMT frame received from the RMC
via the Rx queue is queued back by the driver to the SMT Rx queue for
the firmware to process.  Similarly the firmware uses the SMT Tx queue
to supply the driver with SMT frames which are queued back to the Tx
queue for the RMC to send to the ring.

When a network tap is attached to an FDDI interface handled by `defza'
any incoming SMT frames captured are queued to our usual processing of
network data received, which in turn delivers them to any listening
taps.

However the outgoing SMT frames produced by the firmware bypass our
network protocol stack and are therefore not delivered to taps.  This in
turn means that taps are missing a part of network traffic sent by the
adapter, which may make it more difficult to track down network problems
or do general traffic analysis.

Call `dev_queue_xmit_nit' then in the SMT Tx path, having checked that
a network tap is attached, with a newly-created `dev_nit_active' helper
wrapping the usual condition used in the transmit path.

Signed-off-by: Maciej W. Rozycki 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2018-10-13T04:38:46+00:00

Conflicts were easy to resolve using immediate context mostly,
except the cls_u32.c one where I simply too the entire HEAD
chunk.

Signed-off-by: David S. Miller

net: ipv4: update fnhe_pmtu when first hop's MTU changes

2018-10-11T05:44:46+00:00

Since commit 5aad1de5ea2c ("ipv4: use separate genid for next hop
exceptions"), exceptions get deprecated separately from cached
routes. In particular, administrative changes don't clear PMTU anymore.

As Stefano described in commit e9fa1495d738 ("ipv6: Reflect MTU changes
on PMTU of exceptions for MTU-less routes"), the PMTU discovered before
the local MTU change can become stale:
 - if the local MTU is now lower than the PMTU, that PMTU is now
   incorrect
 - if the local MTU was the lowest value in the path, and is increased,
   we might discover a higher PMTU

Similarly to what commit e9fa1495d738 did for IPv6, update PMTU in those
cases.

If the exception was locked, the discovered PMTU was smaller than the
minimal accepted PMTU. In that case, if the new local MTU is smaller
than the current PMTU, let PMTU discovery figure out if locking of the
exception is still needed.

To do this, we need to know the old link MTU in the NETDEV_CHANGEMTU
notifier. By the time the notifier is called, dev->mtu has been
changed. This patch adds the old MTU as additional information in the
notifier structure, and a new call_netdevice_notifiers_u32() function.

Fixes: 5aad1de5ea2c ("ipv4: use separate genid for next hop exceptions")
Signed-off-by: Sabrina Dubroca 
Reviewed-by: Stefano Brivio 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

net: fix generic XDP to handle if eth header was mangled

2018-10-10T04:59:09+00:00

XDP can modify (and resize) the Ethernet header in the packet.

There is a bug in generic-XDP, because skb->protocol and skb->pkt_type
are setup before reaching (netif_receive_)generic_xdp.

This bug was hit when XDP were popping VLAN headers (changing
eth->h_proto), as skb->protocol still contains VLAN-indication
(ETH_P_8021Q) causing invocation of skb_vlan_untag(skb), which corrupt
the packet (basically popping the VLAN again).

This patch catch if XDP changed eth header in such a way, that SKB
fields needs to be updated.

V2: on request from Song Liu, use ETH_HLEN instead of mac_len,
in __skb_push() as eth_type_trans() use ETH_HLEN in paired skb_pull_inline().

Fixes: d445516966dc ("net: xdp: support xdp generic on virtual devices")
Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: Alexei Starovoitov

net: Add and use skb_list_del_init().

2018-09-10T17:06:54+00:00

It documents what is happening, and eliminates the spurious list
pointer poisoning.

In the long term, in order to get proper list head debugging, we
might want to use the list poison value as the indicator that
an SKB is a singleton and not on a list.

Signed-off-by: David S. Miller