David Ahern reported that 5425077d ("net: ipv6: Add early demux
handler for UDP unicast") breaks udp_l3mdev_accept=0 since early
demux for IPv6 UDP was doing a generic socket lookup which does not
require an exact match. Fix this by making UDPv6 early demux match
connected sockets only.

v1->v2: Take reference to socket after match as suggested by Eric
v2->v3: Add comment before break

Fixes: 5425077d ("net: ipv6: Add early demux handler for UDP unicast")
Reported-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Eric Dumazet <edumazet@google.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Tested-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Certain system process significant unconnected UDP workload.
It would be preferrable to disable UDP early demux for those systems
and enable it for TCP only.

By disabling UDP demux, we see these slight gains on an ARM64 system-
782 -> 788Mbps unconnected single stream UDPv4
633 -> 654Mbps unconnected UDPv4 different sources

The performance impact can change based on CPU architecure and cache
sizes. There will not much difference seen if entire UDP hash table
is in cache.

Both sysctls are enabled by default to preserve existing behavior.

v1->v2: Change function pointer instead of adding conditional as
suggested by Stephen.

v2->v3: Read once in callers to avoid issues due to compiler
optimizations. Also update commit message with the tests.

v3->v4: Store and use read once result instead of querying pointer
again incorrectly.

v4->v5: Refactor to avoid errors due to compilation with IPV6={m,n}
Signed-off-by: NSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Suggested-by: NEric Dumazet <edumazet@google.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Tom Herbert <tom@herbertland.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the case udp_sk(sk)->pending is AF_INET6, udpv6_sendmsg() would
jump to do_append_data, skipping the initialization of sockc.tsflags.
Fix the problem by moving sockc.tsflags initialization earlier.

The bug was detected with KMSAN.

Fixes: c14ac945 ("sock: enable timestamping using control messages")
Signed-off-by: NAlexander Potapenko <glider@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While running a single stream UDPv6 test, we observed that amount
of CPU spent in NET_RX softirq was much greater than UDPv4 for an
equivalent receive rate. The test here was run on an ARM64 based
Android system. On further analysis with perf, we found that UDPv6
was spending significant time in the statistics netfilter targets
which did socket lookup per packet. These statistics rules perform
a lookup when there is no socket associated with the skb. Since
there are multiple instances of these rules based on UID, there
will be equal number of lookups per skb.

By introducing early demux for UDPv6, we avoid the redundant lookups.
This also helped to improve the performance (800Mbps -> 870Mbps) on a
CPU limited system in a single stream UDPv6 receive test with 1450
byte sized datagrams using iperf.

v1->v2: Use IPv6 cookie to validate dst instead of 0 as suggested
by Eric
Signed-off-by: NSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a check on the type of the source address for the case
where the destination address is in6addr_any. If the source is an
IPv4-mapped IPv6 source address, the destination is changed to
::ffff:127.0.0.1, and otherwise the destination is changed to ::1. This
is done in three locations to handle UDP calls to either connect() or
sendmsg() and TCP calls to connect(). Note that udpv6_sendmsg() delays
handling an in6addr_any destination until very late, so the patch only
needs to handle the case where the source is an IPv4-mapped IPv6
address.
Signed-off-by: NJonathan T. Leighton <jtleight@udel.edu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When same struct dst_entry can be used for many different
neighbours we can not use it for pending confirmations.

The datagram protocols can use MSG_CONFIRM to confirm the
neighbour. When used with MSG_PROBE we do not reach the
code where neighbour is confirmed, so we have to do the
same slow lookup by using the dst_confirm_neigh() helper.
When MSG_PROBE is not used, ip_append_data/ip6_append_data
will set the skb flag dst_pending_confirm.
Reported-by: NYueHaibing <yuehaibing@huawei.com>
Fixes: 5110effe ("net: Do delayed neigh confirmation.")
Fixes: f2bb4bed ("ipv4: Cache output routes in fib_info nexthops.")
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dmitry reported that UDP sockets being destroyed would trigger the
WARN_ON(atomic_read(&sk->sk_rmem_alloc)); in inet_sock_destruct()

It turns out we do not properly destroy skb(s) that have wrong UDP
checksum.

Thanks again to syzkaller team.

Fixes : 7c13f97f ("udp: do fwd memory scheduling on dequeue")
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Packets arriving in a VRF currently are delivered to UDP sockets that
aren't bound to any interface. TCP defaults to not delivering packets
arriving in a VRF to unbound sockets. IP route lookup and socket
transmit both assume that unbound means using the default table and
UDP applications that haven't been changed to be aware of VRFs may not
function correctly in this case since they may not be able to handle
overlapping IP address ranges, or be able to send packets back to the
original sender if required.

So add a sysctl, udp_l3mdev_accept, to control this behaviour with it
being analgous to the existing tcp_l3mdev_accept, namely to allow a
process to have a VRF-global listen socket. Have this default to off
as this is the behaviour that users will expect, given that there is
no explicit mechanism to set unmodified VRF-unaware application into a
default VRF.
Signed-off-by: NRobert Shearman <rshearma@brocade.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Tested-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We pass these per-protocol equal functions around in various places, but
we can just have one function that checks the sk->sk_family and then do
the right comparison function.  I've also changed the ipv4 version to
not cast to inet_sock since it is unneeded.
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commits 93821778 ("udp: Fix rcv socket locking") and
f7ad74fe ("net/ipv6/udp: UDP encapsulation: break backlog_rcv into
__udpv6_queue_rcv_skb") UDP backlog handlers were renamed, but UDPlite
was forgotten.

This leads to crashes if UDPlite header is pulled twice, which happens
starting from commit e6afc8ac ("udp: remove headers from UDP packets
before queueing")

Bug found by syzkaller team, thanks a lot guys !

Note that backlog use in UDP/UDPlite is scheduled to be removed starting
from linux-4.10, so this patch is only needed up to linux-4.9

Fixes: 93821778 ("udp: Fix rcv socket locking")
Fixes: f7ad74fe ("net/ipv6/udp: UDP encapsulation: break backlog_rcv into __udpv6_queue_rcv_skb")
Fixes: e6afc8ac ("udp: remove headers from UDP packets before queueing")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UDP_SKB_CB(skb)->partial_cov is located at offset 66 in skb,
requesting a cold cache line being read in cpu cache.

We can avoid this cache line miss for UDP sockets,
as partial_cov has a meaning only for UDPLite.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UDP busy polling is restricted to connected UDP sockets.

This is because sk_busy_loop() only takes care of one NAPI context.

There are cases where it could be extended.

1) Some hosts receive traffic on a single NIC, with one RX queue.

2) Some applications use SO_REUSEPORT and associated BPF filter
   to split the incoming traffic on one UDP socket per RX
queue/thread/cpu

3) Some UDP sockets are used to send/receive traffic for one flow, but
they do not bother with connect()

This patch records the napi_id of first received skb, giving more
reach to busy polling.

Tested:

lpaa23:~# echo 70 >/proc/sys/net/core/busy_read
lpaa24:~# echo 70 >/proc/sys/net/core/busy_read

lpaa23:~# for f in `seq 1 10`; do ./super_netperf 1 -H lpaa24 -t UDP_RR -l 5; done

Before patch :
   27867   28870   37324   41060   41215
   36764   36838   44455   41282   43843
After patch :
   73920   73213   70147   74845   71697
   68315   68028   75219   70082   73707
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Honor udptable parameter that is passed to __udp*_lib_mcast_deliver(),
otherwise udplite broadcast/multicast use the wrong table and it breaks.

Fixes: 2dc41cff ("udp: Use hash2 for long hash1 chains in __udp*_lib_mcast_deliver.")
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit ca065d0c ("udp: no longer use SLAB_DESTROY_BY_RCU")
the udp6_lib_lookup and udp4_lib_lookup functions are only
provided when it is actually possible to call them.

However, moving the callers now caused a link error:

net/built-in.o: In function `nf_sk_lookup_slow_v6':
(.text+0x131a39): undefined reference to `udp6_lib_lookup'
net/ipv4/netfilter/nf_socket_ipv4.o: In function `nf_sk_lookup_slow_v4':
nf_socket_ipv4.c:(.text.nf_sk_lookup_slow_v4+0x114): undefined reference to `udp4_lib_lookup'

This extends the #ifdef so we also provide the functions when
CONFIG_NF_SOCKET_IPV4 or CONFIG_NF_SOCKET_IPV6, respectively
are set.

Fixes: 8db4c5be ("netfilter: move socket lookup infrastructure to nf_socket_ipv{4,6}.c")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

A new argument is added to __skb_recv_datagram to provide
an explicit skb destructor, invoked under the receive queue
lock.
The UDP protocol uses such argument to perform memory
reclaiming on dequeue, so that the UDP protocol does not
set anymore skb->desctructor.
Instead explicit memory reclaiming is performed at close() time and
when skbs are removed from the receive queue.
The in kernel UDP protocol users now need to call a
skb_recv_udp() variant instead of skb_recv_datagram() to
properly perform memory accounting on dequeue.

Overall, this allows acquiring only once the receive queue
lock on dequeue.

Tested using pktgen with random src port, 64 bytes packet,
wire-speed on a 10G link as sender and udp_sink as the receiver,
using an l4 tuple rxhash to stress the contention, and one or more
udp_sink instances with reuseport.

nr sinks	vanilla		patched
1		440		560
3		2150		2300
6		3650		3800
9		4450		4600
12		6250		6450

v1 -> v2:
 - do rmem and allocated memory scheduling under the receive lock
 - do bulk scheduling in first_packet_length() and in udp_destruct_sock()
 - avoid the typdef for the dequeue callback
Suggested-by: NEric Dumazet <edumazet@google.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

So that we can use it even after orphaining the skbuff.
Suggested-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Use the UID in routing lookups made by protocol connect() and
  sendmsg() functions.
- Make sure that routing lookups triggered by incoming packets
  (e.g., Path MTU discovery) take the UID of the socket into
  account.
- For packets not associated with a userspace socket, (e.g., ping
  replies) use UID 0 inside the user namespace corresponding to
  the network namespace the socket belongs to. This allows
  all namespaces to apply routing and iptables rules to
  kernel-originated traffic in that namespaces by matching UID 0.
  This is better than using the UID of the kernel socket that is
  sending the traffic, because the UID of kernel sockets created
  at namespace creation time (e.g., the per-processor ICMP and
  TCP sockets) is the UID of the user that created the socket,
  which might not be mapped in the namespace.

Tested: compiles allnoconfig, allyesconfig, allmodconfig
Tested: https://android-review.googlesource.com/253302Signed-off-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

First bug was added in commit ad6f939a ("ip: Add offset parameter to
ip_cmsg_recv") : Tom missed that ipv4 udp messages could be received on
AF_INET6 socket. ip_cmsg_recv(msg, skb) should have been replaced by
ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr));

Then commit e6afc8ac ("udp: remove headers from UDP packets before
queueing") forgot to adjust the offsets now UDP headers are pulled
before skb are put in receive queue.

Fixes: ad6f939a ("ip: Add offset parameter to ip_cmsg_recv")
Fixes: e6afc8ac ("udp: remove headers from UDP packets before queueing")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Sam Kumar <samanthakumar@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Tested-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Completely avoid default sock memory accounting and replace it
with udp-specific accounting.

Since the new memory accounting model encapsulates completely
the required locking, remove the socket lock on both enqueue and
dequeue, and avoid using the backlog on enqueue.

Be sure to clean-up rx queue memory on socket destruction, using
udp its own sk_destruct.

Tested using pktgen with random src port, 64 bytes packet,
wire-speed on a 10G link as sender and udp_sink as the receiver,
using an l4 tuple rxhash to stress the contention, and one or more
udp_sink instances with reuseport.

nr readers      Kpps (vanilla)  Kpps (patched)
1               170             440
3               1250            2150
6               3000            3650
9               4200            4450
12              5700            6250

v4 -> v5:
  - avoid unneeded test in first_packet_length

v3 -> v4:
  - remove useless sk_rcvqueues_full() call

v2 -> v3:
  - do not set the now unsed backlog_rcv callback

v1 -> v2:
  - add memory pressure support
  - fixed dropwatch accounting for ipv6
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now RCU lookups of ipv6 udp sockets no longer dereference
pinet6 field, we can get rid of udp_v6_clear_sk() helper.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This implements SOCK_DESTROY for UDP sockets similar to what was done
for TCP with commit c1e64e29 ("net: diag: Support destroying TCP
sockets.") A process with a UDP socket targeted for destroy is awakened
and recvmsg fails with ECONNABORTED.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After commit ca065d0c ("udp: no longer use SLAB_DESTROY_BY_RCU")
we do not need this special allocation mode anymore, even if it is
harmless.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After a6127697 ("udp: prevent bugcheck if filter truncates packet
too much"), there followed various other fixes for similar cases such
as f4979fce ("rose: limit sk_filter trim to payload").

Latter introduced a new helper sk_filter_trim_cap(), where we can pass
the trim limit directly to the socket filter handling. Make use of it
here as well with sizeof(struct udphdr) as lower cap limit and drop the
extra skb->len test in UDP's input path.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If socket filter truncates an udp packet below the length of UDP header
in udpv6_queue_rcv_skb() or udp_queue_rcv_skb(), it will trigger a
BUG_ON in skb_pull_rcsum(). This BUG_ON (and therefore a system crash if
kernel is configured that way) can be easily enforced by an unprivileged
user which was reported as CVE-2016-6162. For a reproducer, see
http://seclists.org/oss-sec/2016/q3/8

Fixes: e6afc8ac ("udp: remove headers from UDP packets before queueing")
Reported-by: NMarco Grassi <marco.gra@gmail.com>
Signed-off-by: NMichal Kubecek <mkubecek@suse.cz>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is a corner case in which udp packets belonging to a same
flow are hashed to different socket when hslot->count changes from 10
to 11:

1) When hslot->count <= 10, __udp_lib_lookup() searches udp_table->hash,
and always passes 'daddr' to udp_ehashfn().

2) When hslot->count > 10, __udp_lib_lookup() searches udp_table->hash2,
but may pass 'INADDR_ANY' to udp_ehashfn() if the sockets are bound to
INADDR_ANY instead of some specific addr.

That means when hslot->count changes from 10 to 11, the hash calculated by
udp_ehashfn() is also changed, and the udp packets belonging to a same
flow will be hashed to different socket.

This is easily reproduced:
1) Create 10 udp sockets and bind all of them to 0.0.0.0:40000.
2) From the same host send udp packets to 127.0.0.1:40000, record the
socket index which receives the packets.
3) Create 1 more udp socket and bind it to 0.0.0.0:44096. The number 44096
is 40000 + UDP_HASH_SIZE(4096), this makes the new socket put into the
same hslot as the aformentioned 10 sockets, and makes the hslot->count
change from 10 to 11.
4) From the same host send udp packets to 127.0.0.1:40000, and the socket
index which receives the packets will be different from the one received
in step 2.
This should not happen as the socket bound to 0.0.0.0:44096 should not
change the behavior of the sockets bound to 0.0.0.0:40000.

It's the same case for IPv6, and this patch also fixes that.
Signed-off-by: NSu, Xuemin <suxm@chinanetcenter.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In IPv6 the ToS values are part of the flowlabel in flowi6 and get
extracted during fib rule lookup, but we forgot to correctly initialize
the flowlabel before the routing lookup.

Reported-by: <liam.mcbirnie@boeing.com>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Paul Moore tracked a regression caused by a recent commit, which
mistakenly assumed that sk_filter() could be avoided if socket
had no current BPF filter.

The intent was to avoid udp_lib_checksum_complete() overhead.

But sk_filter() also checks skb_pfmemalloc() and
security_sock_rcv_skb(), so better call it.

Fixes: e6afc8ac ("udp: remove headers from UDP packets before queueing")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NPaul Moore <paul@paul-moore.com>
Tested-by: NPaul Moore <paul@paul-moore.com>
Tested-by: NStephen Smalley <sds@tycho.nsa.gov>
Cc: samanthakumar <samanthakumar@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case we find a socket with encapsulation enabled we should call
the encap_recv function even if just a udp header without payload is
available. The callbacks are responsible for correctly verifying and
dropping the packets.

Also, in case the header validation fails for geneve and vxlan we
shouldn't put the skb back into the socket queue, no one will pick
them up there.  Instead we can simply discard them in the respective
encap_recv functions.
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While testing an OpenStack configuration using VXLANs I saw the following
call trace:

 RIP: 0010:[<ffffffff815fad49>] udp4_lib_lookup_skb+0x49/0x80
 RSP: 0018:ffff88103867bc50  EFLAGS: 00010286
 RAX: ffff88103269bf00 RBX: ffff88103269bf00 RCX: 00000000ffffffff
 RDX: 0000000000004300 RSI: 0000000000000000 RDI: ffff880f2932e780
 RBP: ffff88103867bc60 R08: 0000000000000000 R09: 000000009001a8c0
 R10: 0000000000004400 R11: ffffffff81333a58 R12: ffff880f2932e794
 R13: 0000000000000014 R14: 0000000000000014 R15: ffffe8efbfd89ca0
 FS:  0000000000000000(0000) GS:ffff88103fd80000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000488 CR3: 0000000001c06000 CR4: 00000000001426e0
 Stack:
  ffffffff81576515 ffffffff815733c0 ffff88103867bc98 ffffffff815fcc17
  ffff88103269bf00 ffffe8efbfd89ca0 0000000000000014 0000000000000080
  ffffe8efbfd89ca0 ffff88103867bcc8 ffffffff815fcf8b ffff880f2932e794
 Call Trace:
  [<ffffffff81576515>] ? skb_checksum+0x35/0x50
  [<ffffffff815733c0>] ? skb_push+0x40/0x40
  [<ffffffff815fcc17>] udp_gro_receive+0x57/0x130
  [<ffffffff815fcf8b>] udp4_gro_receive+0x10b/0x2c0
  [<ffffffff81605863>] inet_gro_receive+0x1d3/0x270
  [<ffffffff81589e59>] dev_gro_receive+0x269/0x3b0
  [<ffffffff8158a1b8>] napi_gro_receive+0x38/0x120
  [<ffffffffa0871297>] gro_cell_poll+0x57/0x80 [vxlan]
  [<ffffffff815899d0>] net_rx_action+0x160/0x380
  [<ffffffff816965c7>] __do_softirq+0xd7/0x2c5
  [<ffffffff8107d969>] run_ksoftirqd+0x29/0x50
  [<ffffffff8109a50f>] smpboot_thread_fn+0x10f/0x160
  [<ffffffff8109a400>] ? sort_range+0x30/0x30
  [<ffffffff81096da8>] kthread+0xd8/0xf0
  [<ffffffff81693c82>] ret_from_fork+0x22/0x40
  [<ffffffff81096cd0>] ? kthread_park+0x60/0x60

The following trace is seen when receiving a DHCP request over a flow-based
VXLAN tunnel.  I believe this is caused by the metadata dst having a NULL
dev value and as a result dev_net(dev) is causing a NULL pointer dereference.

To resolve this I am replacing the check for skb_dst(skb)->dev with just
skb->dev.  This makes sense as the callers of this function are usually in
the receive path and as such skb->dev should always be populated.  In
addition other functions in the area where these are called are already
using dev_net(skb->dev) to determine the namespace the UDP packet belongs
in.

Fixes: 63058308 ("udp: Add udp6_lib_lookup_skb and udp4_lib_lookup_skb")
Signed-off-by: NAlexander Duyck <aduyck@mirantis.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the sendmsg function of UDP, raw, ICMP and l2tp sockets, we use local
variables like hlimits, tclass, opt and dontfrag and pass them to corresponding
functions like ip6_make_skb, ip6_append_data and xxx_push_pending_frames.
This is not a good practice and makes it hard to add new parameters.
This fix introduces a new struct ipcm6_cookie similar to ipcm_cookie in
ipv4 and include the above mentioned variables. And we only pass the
pointer to this structure to corresponding functions. This makes it easier
to add new parameters in the future and makes the function cleaner.
Signed-off-by: NWei Wang <weiwan@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UDP uses the generic socket backlog code, and this will soon
be changed to not disable BH when protocol is called back.

We need to use appropriate SNMP accessors.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename ICMP6_INC_STATS_BH() to __ICMP6_INC_STATS()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename UDP_INC_STATS_BH() to __UDP_INC_STATS(),
and UDP6_INC_STATS_BH() to __UDP6_INC_STATS()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the old days (before linux-3.0), SNMP counters were duplicated,
one for user context, and one for BH context.

After commit 8f0ea0fe ("snmp: reduce percpu needs by 50%")
we have a single copy, and what really matters is preemption being
enabled or disabled, since we use this_cpu_inc() or __this_cpu_inc()
respectively.

We therefore kill SNMP_INC_STATS_USER(), SNMP_ADD_STATS_USER(),
NET_INC_STATS_USER(), NET_ADD_STATS_USER(), SCTP_INC_STATS_USER(),
SNMP_INC_STATS64_USER(), SNMP_ADD_STATS64_USER(), TCP_ADD_STATS_USER(),
UDP_INC_STATS_USER(), UDP6_INC_STATS_USER(), and XFRM_INC_STATS_USER()

Following patches will rename __BH helpers to make clear their
usage is not tied to BH being disabled.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a release_cb for UDPv6.  It does a route lookup
and updates sk->sk_dst_cache if it is needed.  It picks up the
left-over job from ip6_sk_update_pmtu() if the sk was owned
by user during the pmtu update.

It takes a rcu_read_lock to protect the __sk_dst_get() operations
because another thread may do ip6_dst_store() without taking the
sk lock (e.g. sendmsg).

Fixes: 45e4fd26 ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception")
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Reported-by: NWei Wang <weiwan@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add externally visible functions to lookup a UDP socket by skb. This
will be used for GRO in UDP sockets. These functions also check
if skb->dst is set, and if it is not skb->dev is used to get dev_net.
This allows calling lookup functions before dst has been set on the
skbuff.
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Enable peeking at UDP datagrams at the offset specified with socket
option SOL_SOCKET/SO_PEEK_OFF. Peek at any datagram in the queue, up
to the end of the given datagram.

Implement the SO_PEEK_OFF semantics introduced in commit ef64a54f
("sock: Introduce the SO_PEEK_OFF sock option"). Increase the offset
on peek, decrease it on regular reads.

When peeking, always checksum the packet immediately, to avoid
recomputation on subsequent peeks and final read.

The socket lock is not held for the duration of udp_recvmsg, so
peek and read operations can run concurrently. Only the last store
to sk_peek_off is preserved.
Signed-off-by: NSam Kumar <samanthakumar@google.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove UDP transport headers before queueing packets for reception.
This change simplifies a follow-up patch to add MSG_PEEK support.
Signed-off-by: NSam Kumar <samanthakumar@google.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Tom Herbert would like not touching UDP socket refcnt for encapsulated
traffic. For this to happen, we need to use normal RCU rules, with a grace
period before freeing a socket. UDP sockets are not short lived in the
high usage case, so the added cost of call_rcu() should not be a concern.

This actually removes a lot of complexity in UDP stack.

Multicast receives no longer need to hold a bucket spinlock.

Note that ip early demux still needs to take a reference on the socket.

Same remark for functions used by xt_socket and xt_PROXY netfilter modules,
but this might be changed later.

Performance for a single UDP socket receiving flood traffic from
many RX queues/cpus.

Simple udp_rx using simple recvfrom() loop :
438 kpps instead of 374 kpps : 17 % increase of the peak rate.

v2: Addressed Willem de Bruijn feedback in multicast handling
 - keep early demux break in __udp4_lib_demux_lookup()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Willem de Bruijn <willemb@google.com>
Tested-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>