Introduce a new getsockopt operation to retrieve the socket cookie
for a specific socket based on the socket fd.  It returns a unique
non-decreasing cookie for each socket.
Tested: https://android-review.googlesource.com/#/c/358163/Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NChenbo Feng <fengc@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sock_recv_ts_and_drops() unconditionally set sk->sk_stamp for
every packet, even if the SOCK_TIMESTAMP flag is not set in the
related socket.
If selinux is enabled, this cause a cache miss for every packet
since sk->sk_stamp and sk->sk_security share the same cacheline.
With this change sk_stamp is set only if the SOCK_TIMESTAMP
flag is set, and is cleared for the first packet, so that the user
perceived behavior is unchanged.

This gives up to 5% speed-up under udp-flood with small packets.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This socket option returns the NAPI ID associated with the queue on which
the last frame is received. This information can be used by the apps to
split the incoming flows among the threads based on the Rx queue on which
they are received.

If the NAPI ID actually represents a sender_cpu then the value is ignored
and 0 is returned.
Signed-off-by: NSridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: NAlexander Duyck <alexander.h.duyck@intel.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the core functionality in sk_busy_loop() to napi_busy_loop() and
make it independent of sk.

This enables re-using this function in epoll busy loop implementation.
Signed-off-by: NSridhar Samudrala <sridhar.samudrala@intel.com>
Signed-off-by: NAlexander Duyck <alexander.h.duyck@intel.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In sk_clone_lock(), we create a new socket and inherit most of the
parent's members via sock_copy() which memcpy()'s various sections.
Now, in case the parent socket had a BPF socket filter attached,
then newsk->sk_filter points to the same instance as the original
sk->sk_filter.

sk_filter_charge() is then called on the newsk->sk_filter to take a
reference and should that fail due to hitting max optmem, we bail
out and release the newsk instance.

The issue is that commit 278571ba ("net: filter: simplify socket
charging") wrongly combined the dismantle path with the failure path
of xfrm_sk_clone_policy(). This means, even when charging failed, we
call sk_free_unlock_clone() on the newsk, which then still points to
the same sk_filter as the original sk.

Thus, sk_free_unlock_clone() calls into __sk_destruct() eventually
where it tests for present sk_filter and calls sk_filter_uncharge()
on it, which potentially lets sk_omem_alloc wrap around and releases
the eBPF prog and sk_filter structure from the (still intact) parent.

Fix it by making sure that when sk_filter_charge() failed, we reset
newsk->sk_filter back to NULL before passing to sk_free_unlock_clone(),
so that we don't mess with the parents sk_filter.

Only if xfrm_sk_clone_policy() fails, we did reach the point where
either the parent's filter was NULL and as a result newsk's as well
or where we previously had a successful sk_filter_charge(), thus for
that case, we do need sk_filter_uncharge() to release the prior taken
reference on sk_filter.

Fixes: 278571ba ("net: filter: simplify socket charging")
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allows reading of SK_MEMINFO_VARS via socket option. This way an
application can get all meminfo related information in single socket
option call instead of multiple calls.

Adds helper function, sk_get_meminfo(), and uses that for both
getsockopt and sock_diag_put_meminfo().

Suggested by Eric Dumazet.
Signed-off-by: NJosh Hunt <johunt@akamai.com>
Reviewed-by: NJason Baron <jbaron@akamai.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I mistakenly added the code to release sk->sk_frag in
sk_common_release() instead of sk_destruct()

TCP sockets using sk->sk_allocation == GFP_ATOMIC do no call
sk_common_release() at close time, thus leaking one (order-3) page.

iSCSI is using such sockets.

Fixes: 5640f768 ("net: use a per task frag allocator")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Lockdep issues a circular dependency warning when AFS issues an operation
through AF_RXRPC from a context in which the VFS/VM holds the mmap_sem.

The theory lockdep comes up with is as follows:

 (1) If the pagefault handler decides it needs to read pages from AFS, it
     calls AFS with mmap_sem held and AFS begins an AF_RXRPC call, but
     creating a call requires the socket lock:

	mmap_sem must be taken before sk_lock-AF_RXRPC

 (2) afs_open_socket() opens an AF_RXRPC socket and binds it.  rxrpc_bind()
     binds the underlying UDP socket whilst holding its socket lock.
     inet_bind() takes its own socket lock:

	sk_lock-AF_RXRPC must be taken before sk_lock-AF_INET

 (3) Reading from a TCP socket into a userspace buffer might cause a fault
     and thus cause the kernel to take the mmap_sem, but the TCP socket is
     locked whilst doing this:

	sk_lock-AF_INET must be taken before mmap_sem

However, lockdep's theory is wrong in this instance because it deals only
with lock classes and not individual locks.  The AF_INET lock in (2) isn't
really equivalent to the AF_INET lock in (3) as the former deals with a
socket entirely internal to the kernel that never sees userspace.  This is
a limitation in the design of lockdep.

Fix the general case by:

 (1) Double up all the locking keys used in sockets so that one set are
     used if the socket is created by userspace and the other set is used
     if the socket is created by the kernel.

 (2) Store the kern parameter passed to sk_alloc() in a variable in the
     sock struct (sk_kern_sock).  This informs sock_lock_init(),
     sock_init_data() and sk_clone_lock() as to the lock keys to be used.

     Note that the child created by sk_clone_lock() inherits the parent's
     kern setting.

 (3) Add a 'kern' parameter to ->accept() that is analogous to the one
     passed in to ->create() that distinguishes whether kernel_accept() or
     sys_accept4() was the caller and can be passed to sk_alloc().

     Note that a lot of accept functions merely dequeue an already
     allocated socket.  I haven't touched these as the new socket already
     exists before we get the parameter.

     Note also that there are a couple of places where I've made the accepted
     socket unconditionally kernel-based:

	irda_accept()
	rds_rcp_accept_one()
	tcp_accept_from_sock()

     because they follow a sock_create_kern() and accept off of that.

Whilst creating this, I noticed that lustre and ocfs don't create sockets
through sock_create_kern() and thus they aren't marked as for-kernel,
though they appear to be internal.  I wonder if these should do that so
that they use the new set of lock keys.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently the sock queue's spin locks get their lockdep
classes by the default init_spin_lock() initializer:
all socket families get - usually, see below - a single
class for rx, another specific class for tx, etc.
This can lead to false positive lockdep splat, as
reported by Andrey.
Moreover there are two separate initialization points
for the sock queues, one in sk_clone_lock() and one
in sock_init_data(), so that e.g. the rx queue lock
can get one of two possible, different classes, depending
on the socket being cloned or not.
This change tries to address the above, setting explicitly
a per address family lockdep class for each queue's
spinlock. Also, move the duplicated initialization code to a
single location.

v1 -> v2:
 - renamed the init helper

rfc -> v1:
 - no changes, tested with several different workload
Suggested-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When handling problems in cloning a socket with the sk_clone_locked()
function we need to perform several steps that were open coded in it and
its callers, so introduce a routine to avoid this duplication:
sk_free_unlock_clone().

Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/n/net-ui6laqkotycunhtmqryl9bfx@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The USEC_PER_SEC is used once in sock_set_timeout as the max value of
tv_usec. But there are other similar codes which use the literal
1000000 in this file.
It is minor cleanup to keep consitent.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add new sock flag to allow sockets to confirm neighbour.
When same struct dst_entry can be used for many different
neighbours we can not use it for pending confirmations.
As not all call paths lock the socket use full word for
the flag.

Add sk_dst_confirm as replacement for dst_confirm when
called for received packets.
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When introducing the new socket family AF_SMC in
commit ac713874 ("smc: establish new socket family"),
a typo in af_family_clock_key_strings has slipped in.
This patch repairs it.
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Fixes: ac713874 ("smc: establish new socket family")
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit bdabad3e ("net: Add Qualcomm IPC router") introduced a
new address family. Update the family name tables accordingly so
that the lockdep initialization can use the proper names for this
family.

Cc: Courtney Cavin <courtney.cavin@sonymobile.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: NSuman Anna <s-anna@ti.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* enable smc module loading and unloading
 * register new socket family
 * basic smc socket creation and deletion
 * use backing TCP socket to run CLC (Connection Layer Control)
   handshake of SMC protocol
 * Setup for infiniband traffic is implemented in follow-on patches.
   For now fallback to TCP socket is always used.
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: NUtz Bacher <utz.bacher@de.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Direct call of tcp_set_keepalive() function from protocol-agnostic
sock_setsockopt() function in net/core/sock.c violates network
layering. And newly introduced protocol (SMC-R) will need its own
keepalive function. Therefore, add "keepalive" function pointer
to "struct proto", and call it from sock_setsockopt() via this pointer.
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: NUtz Bacher <utz.bacher@de.ibm.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>

CAP_NET_ADMIN users should not be allowed to set negative
sk_sndbuf or sk_rcvbuf values, as it can lead to various memory
corruptions, crashes, OOM...

Note that before commit 82981930 ("net: cleanups in
sock_setsockopt()"), the bug was even more serious, since SO_SNDBUF
and SO_RCVBUF were vulnerable.

This needs to be backported to all known linux kernels.

Again, many thanks to syzkaller team for discovering this gem.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch exports the sender chronograph stats via the socket
SO_TIMESTAMPING channel. Currently we can instrument how long a
particular application unit of data was queued in TCP by tracking
SOF_TIMESTAMPING_TX_SOFTWARE and SOF_TIMESTAMPING_TX_SCHED. Having
these sender chronograph stats exported simultaneously along with
these timestamps allow further breaking down the various sender
limitation.  For example, a video server can tell if a particular
chunk of video on a connection takes a long time to deliver because
TCP was experiencing small receive window. It is not possible to
tell before this patch without packet traces.

To prepare these stats, the user needs to set
SOF_TIMESTAMPING_OPT_STATS and SOF_TIMESTAMPING_OPT_TSONLY flags
while requesting other SOF_TIMESTAMPING TX timestamps. When the
timestamps are available in the error queue, the stats are returned
in a separate control message of type SCM_TIMESTAMPING_OPT_STATS,
in a list of TLVs (struct nlattr) of types: TCP_NLA_BUSY_TIME,
TCP_NLA_RWND_LIMITED, TCP_NLA_SNDBUF_LIMITED. Unit is microsecond.
Signed-off-by: NFrancis Yan <francisyyan@gmail.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Similar to commit 14135f30 ("inet: fix sleeping inside inet_wait_for_connect()"),
sk_wait_event() needs to fix too, because release_sock() is blocking,
it changes the process state back to running after sleep, which breaks
the previous prepare_to_wait().

Switch to the new wait API.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Protocol sockets (struct sock) don't have UIDs, but most of the
time, they map 1:1 to userspace sockets (struct socket) which do.

Various operations such as the iptables xt_owner match need
access to the "UID of a socket", and do so by following the
backpointer to the struct socket. This involves taking
sk_callback_lock and doesn't work when there is no socket
because userspace has already called close().

Simplify this by adding a sk_uid field to struct sock whose value
matches the UID of the corresponding struct socket. The semantics
are as follows:

1. Whenever sk_socket is non-null: sk_uid is the same as the UID
   in sk_socket, i.e., matches the return value of sock_i_uid.
   Specifically, the UID is set when userspace calls socket(),
   fchown(), or accept().
2. When sk_socket is NULL, sk_uid is defined as follows:
   - For a socket that no longer has a sk_socket because
     userspace has called close(): the previous UID.
   - For a cloned socket (e.g., an incoming connection that is
     established but on which userspace has not yet called
     accept): the UID of the socket it was cloned from.
   - For a socket that has never had an sk_socket: UID 0 inside
     the user namespace corresponding to the network namespace
     the socket belongs to.

Kernel sockets created by sock_create_kern are a special case
of #1 and sk_uid is the user that created them. For kernel
sockets created at network namespace creation time, such as the
per-processor ICMP and TCP sockets, this is the user that created
the network namespace.
Signed-off-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Andrey Konovalov reported following error while fuzzing with syzkaller :

IPv4: Attempt to release alive inet socket ffff880068e98940
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 1 PID: 3905 Comm: a.out Not tainted 4.9.0-rc3+ #333
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88006b9e0000 task.stack: ffff880068770000
RIP: 0010:[<ffffffff819ead5f>]  [<ffffffff819ead5f>]
selinux_socket_sock_rcv_skb+0xff/0x6a0 security/selinux/hooks.c:4639
RSP: 0018:ffff8800687771c8  EFLAGS: 00010202
RAX: ffff88006b9e0000 RBX: 1ffff1000d0eee3f RCX: 1ffff1000d1d312a
RDX: 1ffff1000d1d31a6 RSI: dffffc0000000000 RDI: 0000000000000010
RBP: ffff880068777360 R08: 0000000000000000 R09: 0000000000000002
R10: dffffc0000000000 R11: 0000000000000006 R12: ffff880068e98940
R13: 0000000000000002 R14: ffff880068777338 R15: 0000000000000000
FS:  00007f00ff760700(0000) GS:ffff88006cd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020008000 CR3: 000000006a308000 CR4: 00000000000006e0
Stack:
 ffff8800687771e0 ffffffff812508a5 ffff8800686f3168 0000000000000007
 ffff88006ac8cdfc ffff8800665ea500 0000000041b58ab3 ffffffff847b5480
 ffffffff819eac60 ffff88006b9e0860 ffff88006b9e0868 ffff88006b9e07f0
Call Trace:
 [<ffffffff819c8dd5>] security_sock_rcv_skb+0x75/0xb0 security/security.c:1317
 [<ffffffff82c2a9e7>] sk_filter_trim_cap+0x67/0x10e0 net/core/filter.c:81
 [<ffffffff82b81e60>] __sk_receive_skb+0x30/0xa00 net/core/sock.c:460
 [<ffffffff838bbf12>] dccp_v4_rcv+0xdb2/0x1910 net/dccp/ipv4.c:873
 [<ffffffff83069d22>] ip_local_deliver_finish+0x332/0xad0
net/ipv4/ip_input.c:216
 [<     inline     >] NF_HOOK_THRESH ./include/linux/netfilter.h:232
 [<     inline     >] NF_HOOK ./include/linux/netfilter.h:255
 [<ffffffff8306abd2>] ip_local_deliver+0x1c2/0x4b0 net/ipv4/ip_input.c:257
 [<     inline     >] dst_input ./include/net/dst.h:507
 [<ffffffff83068500>] ip_rcv_finish+0x750/0x1c40 net/ipv4/ip_input.c:396
 [<     inline     >] NF_HOOK_THRESH ./include/linux/netfilter.h:232
 [<     inline     >] NF_HOOK ./include/linux/netfilter.h:255
 [<ffffffff8306b82f>] ip_rcv+0x96f/0x12f0 net/ipv4/ip_input.c:487
 [<ffffffff82bd9fb7>] __netif_receive_skb_core+0x1897/0x2a50 net/core/dev.c:4213
 [<ffffffff82bdb19a>] __netif_receive_skb+0x2a/0x170 net/core/dev.c:4251
 [<ffffffff82bdb493>] netif_receive_skb_internal+0x1b3/0x390 net/core/dev.c:4279
 [<ffffffff82bdb6b8>] netif_receive_skb+0x48/0x250 net/core/dev.c:4303
 [<ffffffff8241fc75>] tun_get_user+0xbd5/0x28a0 drivers/net/tun.c:1308
 [<ffffffff82421b5a>] tun_chr_write_iter+0xda/0x190 drivers/net/tun.c:1332
 [<     inline     >] new_sync_write fs/read_write.c:499
 [<ffffffff8151bd44>] __vfs_write+0x334/0x570 fs/read_write.c:512
 [<ffffffff8151f85b>] vfs_write+0x17b/0x500 fs/read_write.c:560
 [<     inline     >] SYSC_write fs/read_write.c:607
 [<ffffffff81523184>] SyS_write+0xd4/0x1a0 fs/read_write.c:599
 [<ffffffff83fc02c1>] entry_SYSCALL_64_fastpath+0x1f/0xc2

It turns out DCCP calls __sk_receive_skb(), and this broke when
lookups no longer took a reference on listeners.

Fix this issue by adding a @refcounted parameter to __sk_receive_skb(),
so that sock_put() is used only when needed.

Fixes: 3b24d854 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NAndrey Konovalov <andreyknvl@google.com>
Tested-by: NAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

At accept() time, it is possible the parent has a non zero
sk_err_soft, leftover from a prior error.

Make sure we do not leave this value in the child, as it
makes future getsockopt(SO_ERROR) calls quite unreliable.
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>

Basic sock operations that udp code can use with its own
memory accounting schema. No functional change is introduced
in the existing APIs.

v4 -> v5:
  - avoid whitespace changes

v2 -> v4:
  - avoid exporting __sock_enqueue_skb

v1 -> v2:
  - avoid export sock_rmem_free
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>

The cgroup core and the memory controller need to track socket ownership
for different purposes, but the tracking sites being entirely different
is kind of ugly.

Be a better citizen and rename the memory controller callbacks to match
the cgroup core callbacks, then move them to the same place.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20160914194846.11153-3-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When a socket is cloned, the associated sock_cgroup_data is duplicated
but not its reference on the cgroup.  As a result, the cgroup reference
count will underflow when both sockets are destroyed later on.

Fixes: bd1060a1 ("sock, cgroup: add sock->sk_cgroup")
Link: http://lkml.kernel.org/r/20160914194846.11153-2-hannes@cmpxchg.orgSigned-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: <stable@vger.kernel.org>	[4.5+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We no longer use this handler, we can delete it.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since we no longer use SLAB_DESTROY_BY_RCU for UDP,
we do not need sk_prot_clear_portaddr_nulls() helper.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dccp verifies packet integrity, including length, at initial rcv in
dccp_invalid_packet, later pulls headers in dccp_enqueue_skb.

A call to sk_filter in-between can cause __skb_pull to wrap skb->len.
skb_copy_datagram_msg interprets this as a negative value, so
(correctly) fails with EFAULT. The negative length is reported in
ioctl SIOCINQ or possibly in a DCCP_WARN in dccp_close.

Introduce an sk_receive_skb variant that caps how small a filter
program can trim packets, and call this in dccp with the header
length. Excessively trimmed packets are now processed normally and
queued for reception as 0B payloads.

Fixes: 7c657876 ("[DCCP]: Initial implementation")
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sergei Trofimovich reported that pulse audio sends SCM_CREDENTIALS
as a control message to TCP. Since __sock_cmsg_send does not
support SCM_RIGHTS and SCM_CREDENTIALS, it returns an error and
hence breaks pulse audio over TCP.

SCM_RIGHTS and SCM_CREDENTIALS are sent on the SOL_SOCKET layer
but they semantically belong to SOL_UNIX. Since all
cmsg-processing functions including sock_cmsg_send ignore control
messages of other layers, it is best to ignore SCM_RIGHTS
and SCM_CREDENTIALS for consistency (and also for fixing pulse
audio over TCP).

Fixes: c14ac945 ("sock: enable timestamping using control messages")
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Reported-by: NSergei Trofimovich <slyfox@gentoo.org>
Tested-by: NSergei Trofimovich <slyfox@gentoo.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Hosts sending lot of ACK packets exhibit high sock_wfree() cost
because of cache line miss to test SOCK_USE_WRITE_QUEUE

We could move this flag close to sk_wmem_alloc but it is better
to perform the atomic_sub_and_test() on a clean cache line,
as it avoid one extra bus transaction.

skb_orphan_partial() can also have a fast track for packets that either
are TCP acks, or already went through another skb_orphan_partial()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Large sendmsg()/write() hold socket lock for the duration of the call,
unless sk->sk_sndbuf limit is hit. This is bad because incoming packets
are parked into socket backlog for a long time.
Critical decisions like fast retransmit might be delayed.
Receivers have to maintain a big out of order queue with additional cpu
overhead, and also possible stalls in TX once windows are full.

Bidirectional flows are particularly hurt since the backlog can become
quite big if the copy from user space triggers IO (page faults)

Some applications learnt to use sendmsg() (or sendmmsg()) with small
chunks to avoid this issue.

Kernel should know better, right ?

Add a generic sk_flush_backlog() helper and use it right
before a new skb is allocated. Typically we put 64KB of payload
per skb (unless MSG_EOR is requested) and checking socket backlog
every 64KB gives good results.

As a matter of fact, tests with TSO/GSO disabled give very nice
results, as we manage to keep a small write queue and smaller
perceived rtt.

Note that sk_flush_backlog() maintains socket ownership,
so is not equivalent to a {release_sock(sk); lock_sock(sk);},
to ensure implicit atomicity rules that sendmsg() was
giving to (possibly buggy) applications.

In this simple implementation, I chose to not call tcp_release_cb(),
but we might consider this later.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Socket backlog processing is a major latency source.

With current TCP socket sk_rcvbuf limits, I have sampled __release_sock()
holding cpu for more than 5 ms, and packets being dropped by the NIC
once ring buffer is filled.

All users are now ready to be called from process context,
we can unblock BH and let interrupts be serviced faster.

cond_resched_softirq() could be removed, as it has no more user.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

During release_sock we use callbacks to finish the processing
of outstanding skbs on the socket. We actually are still locked,
sk_locked.owned == 1, but we already told lockdep that the mutex
is released. This could lead to false positives in lockdep for
lockdep_sock_is_held (we don't hold the slock spinlock during processing
the outstanding skbs).

I took over this patch from Eric Dumazet and tested it.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is for the recent kcm driver, which introduces AF_KCM(41) in
b7ac4eb(kcm: Kernel Connection Multiplexor module).
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: Signed-off-by: Tom 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>

Goal: packets dropped by a listener are accounted for.

This adds tcp_listendrop() helper, and clears sk_drops in sk_clone_lock()
so that children do not inherit their parent drop count.

Note that we no longer increment LINUX_MIB_LISTENDROPS counter when
sending a SYNCOOKIE, since the SYN packet generated a SYNACK.
We already have a separate LINUX_MIB_SYNCOOKIESSENT
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We want a generic way to insert an RCU grace period before socket
freeing for cases where RCU_SLAB_DESTROY_BY_RCU is adding too
much overhead.

SLAB_DESTROY_BY_RCU strict rules force us to take a reference
on the socket sk_refcnt, and it is a performance problem for UDP
encapsulation, or TCP synflood behavior, as many CPUs might
attempt the atomic operations on a shared sk_refcnt

UDP sockets and TCP listeners can set SOCK_RCU_FREE so that their
lookup can use traditional RCU rules, without refcount changes.
They can set the flag only once hashed and visible by other cpus.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Tested-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Accept SO_TIMESTAMPING in control messages of the SOL_SOCKET level
as a basis to accept timestamping requests per write.

This implementation only accepts TX recording flags (i.e.,
SOF_TIMESTAMPING_TX_HARDWARE, SOF_TIMESTAMPING_TX_SOFTWARE,
SOF_TIMESTAMPING_TX_SCHED, and SOF_TIMESTAMPING_TX_ACK) in
control messages. Users need to set reporting flags (e.g.,
SOF_TIMESTAMPING_OPT_ID) per socket via socket options.

This commit adds a tsflags field in sockcm_cookie which is
set in __sock_cmsg_send. It only override the SOF_TIMESTAMPING_TX_*
bits in sockcm_cookie.tsflags allowing the control message
to override the recording behavior per write, yet maintaining
the value of other flags.

This patch implements validating the control message and setting
tsflags in struct sockcm_cookie. Next commits in this series will
actually implement timestamping per write for different protocols.
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>