linux-stable.git/drivers/net/tun.c, branch v6.0

tun: support not enabling carrier in TUNSETIFF

2022-09-23T11:02:03+00:00

This change adds support for not enabling carrier during TUNSETIFF
interface creation by specifying the IFF_NO_CARRIER flag.

Our tests make heavy use of tun interfaces. In some scenarios, the test
process creates the interface but another process brings it up after the
interface is discovered via netlink notification. In that case, it is
not possible to create a tun/tap interface with carrier off without it
racing against the bring up. Immediately setting carrier off via
TUNSETCARRIER is still too late.

Signed-off-by: Patrick Rohr 
Cc: Maciej Żenczykowski 
Cc: Lorenzo Colitti 
Cc: Jason Wang 
Cc: Stephen Hemminger 
Cc: Nicolas Dichtel 
Reviewed-by: Maciej Żenczykowski 
Acked-by: Jason Wang 
Reviewed-by: Nicolas Dichtel 
Signed-off-by: David S. Miller

net: tun: avoid disabling NAPI twice

2022-06-30T18:34:10+00:00

Eric reports that syzbot made short work out of my speculative
fix. Indeed when queue gets detached its tfile->tun remains,
so we would try to stop NAPI twice with a detach(), close()
sequence.

Alternative fix would be to move tun_napi_disable() to
tun_detach_all() and let the NAPI run after the queue
has been detached.

Fixes: a8fc8cb5692a ("net: tun: stop NAPI when detaching queues")
Reported-by: syzbot 
Reported-by: Eric Dumazet 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20220629181911.372047-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: tun: stop NAPI when detaching queues

2022-06-28T04:48:01+00:00

While looking at a syzbot report I noticed the NAPI only gets
disabled before it's deleted. I think that user can detach
the queue before destroying the device and the NAPI will never
be stopped.

Fixes: 943170998b20 ("tun: enable NAPI for TUN/TAP driver")
Acked-by: Petar Penkov 
Link: https://lore.kernel.org/r/20220623042105.2274812-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: tun: unlink NAPI from device on destruction

2022-06-24T23:28:08+00:00

Syzbot found a race between tun file and device destruction.
NAPIs live in struct tun_file which can get destroyed before
the netdev so we have to del them explicitly. The current
code is missing deleting the NAPI if the queue was detached
first.

Fixes: 943170998b20 ("tun: enable NAPI for TUN/TAP driver")
Reported-by: syzbot+b75c138e9286ac742647@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20220623042039.2274708-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

net: switch to netif_napi_add_tx()

2022-05-05T22:54:12+00:00

Switch net callers to the new API not requiring
the NAPI_POLL_WEIGHT argument.

Acked-by: Florian Fainelli 
Reviewed-by: Alex Elder 
Acked-by: Mat Martineau 
Acked-by: Alexandra Winter 
Link: https://lore.kernel.org/r/20220504163725.550782-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

tun: annotate access to queue->trans_start

2022-04-14T06:30:09+00:00

Commit 5337824f4dc4 ("net: annotate accesses to queue->trans_start")
introduced a new helper, txq_trans_cond_update, to update
queue->trans_start using WRITE_ONCE. One snippet in drivers/net/tun.c
was missed, as it was introduced roughly at the same time.

Fixes: 5337824f4dc4 ("net: annotate accesses to queue->trans_start")
Cc: Eric Dumazet 
Signed-off-by: Antoine Tenart 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20220412135852.466386-1-atenart@kernel.org
Signed-off-by: Paolo Abeni

net: add per-cpu storage and net->core_stats

2022-03-12T07:17:24+00:00

Before adding yet another possibly contended atomic_long_t,
it is time to add per-cpu storage for existing ones:
 dev->tx_dropped, dev->rx_dropped, and dev->rx_nohandler

Because many devices do not have to increment such counters,
allocate the per-cpu storage on demand, so that dev_get_stats()
does not have to spend considerable time folding zero counters.

Note that some drivers have abused these counters which
were supposed to be only used by core networking stack.

v4: should use per_cpu_ptr() in dev_get_stats() (Jakub)
v3: added a READ_ONCE() in netdev_core_stats_alloc() (Paolo)
v2: add a missing include (reported by kernel test robot )
    Change in netdev_core_stats_alloc() (Jakub)

Signed-off-by: Eric Dumazet 
Cc: jeffreyji 
Reviewed-by: Brian Vazquez 
Reviewed-by: Jakub Kicinski 
Acked-by: Paolo Abeni 
Link: https://lore.kernel.org/r/20220311051420.2608812-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski

tun: vxlan: Use netif_rx().

2022-03-07T11:40:40+00:00

Since commit
   baebdf48c3600 ("net: dev: Makes sure netif_rx() can be invoked in any context.")

the function netif_rx() can be used in preemptible/thread context as
well as in interrupt context.

Use netif_rx().

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: David S. Miller

net: tun: track dropped skb via kfree_skb_reason()

2022-03-06T11:04:01+00:00

The TUN can be used as vhost-net backend. E.g, the tun_net_xmit() is the
interface to forward the skb from TUN to vhost-net/virtio-net.

However, there are many "goto drop" in the TUN driver. Therefore, the
kfree_skb_reason() is involved at each "goto drop" to help userspace
ftrace/ebpf to track the reason for the loss of packets.

The below reasons are introduced:

- SKB_DROP_REASON_DEV_READY
- SKB_DROP_REASON_NOMEM
- SKB_DROP_REASON_HDR_TRUNC
- SKB_DROP_REASON_TAP_FILTER
- SKB_DROP_REASON_TAP_TXFILTER

Cc: Joao Martins 
Cc: Joe Jin 
Signed-off-by: Dongli Zhang 
Signed-off-by: David S. Miller

net: tun: split run_ebpf_filter() and pskb_trim() into different "if statement"

2022-03-06T11:04:01+00:00

No functional change.

Just to split the if statement into different conditions to use
kfree_skb_reason() to trace the reason later.

Cc: Joao Martins 
Cc: Joe Jin 
Signed-off-by: Dongli Zhang 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller