In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.

Replace the existing empty member position markers "headers_start" and
"headers_end" with a struct_group(). This will allow memcpy() and sizeof()
to more easily reason about sizes, and improve readability.

"pahole" shows no size nor member offset changes to struct sk_buff.
"objdump -d" shows no object code changes (outside of WARNs affected by
source line number changes).
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NGustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com> # drivers/net/wireguard/*
Link: https://lore.kernel.org/lkml/20210728035006.GD35706@embeddedorSigned-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation for using the struct_group() macro in struct sk_buff,
move the conditional preprocessor directives out of the region of struct
sk_buff that will be enclosed by struct_group(). While GCC and Clang are
happy with conditional preprocessor directives here, sparse is not, even
under -Wno-directive-within-macro[1], as would be seen under a C=1 build:

net/core/filter.c: note: in included file (through include/linux/netlink.h, include/linux/sock_diag.h):
./include/linux/skbuff.h:820:1: warning: directive in macro's argument list
./include/linux/skbuff.h:822:1: warning: directive in macro's argument list
./include/linux/skbuff.h:846:1: warning: directive in macro's argument list
./include/linux/skbuff.h:848:1: warning: directive in macro's argument list

Additionally remove empty macro argument definitions and usage.

"objdump -d" shows no object code differences.

[1] https://www.spinics.net/lists/linux-sparse/msg10857.htmlSigned-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add missing entries to fix these "make htmldocs" warnings.

./include/linux/skbuff.h:953: warning: Function parameter or member 'll_node' not described in 'sk_buff'
./include/net/sock.h:540: warning: Function parameter or member 'defer_list' not described in 'sock'

Fixes: f35f8219 ("tcp: defer skb freeing after socket lock is released")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp recvmsg() (or rx zerocopy) spends a fair amount of time
freeing skbs after their payload has been consumed.

A typical ~64KB GRO packet has to release ~45 page
references, eventually going to page allocator
for each of them.

Currently, this freeing is performed while socket lock
is held, meaning that there is a high chance that
BH handler has to queue incoming packets to tcp socket backlog.

This can cause additional latencies, because the user
thread has to process the backlog at release_sock() time,
and while doing so, additional frames can be added
by BH handler.

This patch adds logic to defer these frees after socket
lock is released, or directly from BH handler if possible.

Being able to free these skbs from BH handler helps a lot,
because this avoids the usual alloc/free assymetry,
when BH handler and user thread do not run on same cpu or
NUMA node.

One cpu can now be fully utilized for the kernel->user copy,
and another cpu is handling BH processing and skb/page
allocs/frees (assuming RFS is not forcing use of a single CPU)

Tested:
 100Gbit NIC
 Max throughput for one TCP_STREAM flow, over 10 runs

MTU : 1500
Before: 55 Gbit
After:  66 Gbit

MTU : 4096+(headers)
Before: 82 Gbit
After:  95 Gbit
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Eliminate the follow smatch warning:

./include/linux/skbuff.h:4229 skb_remcsum_process() warn: inconsistent
indenting.
Reported-by: NAbaci Robot <abaci@linux.alibaba.com>
Signed-off-by: NJiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Track skbs containing only zerocopy data and avoid charging them to
kernel memory to correctly account the memory utilization for
msg_zerocopy. All of the data in such skbs is held in user pages which
are already accounted to user. Before this change, they are charged
again in kernel in __zerocopy_sg_from_iter. The charging in kernel is
excessive because data is not being copied into skb frags. This
excessive charging can lead to kernel going into memory pressure
state which impacts all sockets in the system adversely. Mark pure
zerocopy skbs with a SKBFL_PURE_ZEROCOPY flag and remove
charge/uncharge for data in such skbs.

Initially, an skb is marked pure zerocopy when it is empty and in
zerocopy path. skb can then change from a pure zerocopy skb to mixed
data skb (zerocopy and copy data) if it is at tail of write queue and
there is room available in it and non-zerocopy data is being sent in
the next sendmsg call. At this time sk_mem_charge is done for the pure
zerocopied data and the pure zerocopy flag is unmarked. We found that
this happens very rarely on workloads that pass MSG_ZEROCOPY.

A pure zerocopy skb can later be coalesced into normal skb if they are
next to each other in queue but this patch prevents coalescing from
happening. This avoids complexity of charging when skb downgrades from
pure zerocopy to mixed. This is also rare.

In sk_wmem_free_skb, if it is a pure zerocopy skb, an sk_mem_uncharge
for SKB_TRUESIZE(skb_end_offset(skb)) is done for sk_mem_charge in
tcp_skb_entail for an skb without data.

Testing with the msg_zerocopy.c benchmark between two hosts(100G nics)
with zerocopy showed that before this patch the 'sock' variable in
memory.stat for cgroup2 that tracks sum of sk_forward_alloc,
sk_rmem_alloc and sk_wmem_queued is around 1822720 and with this
change it is 0. This is due to no charge to sk_forward_alloc for
zerocopy data and shows memory utilization for kernel is lowered.

With this commit we don't see the warning we saw in previous commit
which resulted in commit 84882cf7.
Signed-off-by: NTalal Ahmad <talalahmad@google.com>
Acked-by: NArjun Roy <arjunroy@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While commit 097b9146 ("net: fix up truesize of cloned
skb in skb_prepare_for_shift()") fixed immediate issues found
when KFENCE was enabled/tested, there are still similar issues,
when tcp_trim_head() hits KFENCE while the master skb
is cloned.

This happens under heavy networking TX workloads,
when the TX completion might be delayed after incoming ACK.

This patch fixes the WARNING in sk_stream_kill_queues
when sk->sk_mem_queued/sk->sk_forward_alloc are not zero.

Fixes: d3fb45f3 ("mm, kfence: insert KFENCE hooks for SLAB")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NMarco Elver <elver@google.com>
Link: https://lore.kernel.org/r/20211102004555.1359210-1-eric.dumazet@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

This reverts commit f1a456f8.

  WARNING: CPU: 1 PID: 6819 at net/core/skbuff.c:5429 skb_try_coalesce+0x78b/0x7e0
  CPU: 1 PID: 6819 Comm: xxxxxxx Kdump: loaded Tainted: G S                5.15.0-04194-gd852503f7711 #16
  RIP: 0010:skb_try_coalesce+0x78b/0x7e0
  Code: e8 2a bf 41 ff 44 8b b3 bc 00 00 00 48 8b 7c 24 30 e8 19 c0 41 ff 44 89 f0 48 03 83 c0 00 00 00 48 89 44 24 40 e9 47 fb ff ff <0f> 0b e9 ca fc ff ff 4c 8d 70 ff 48 83 c0 07 48 89 44 24 38 e9 61
  RSP: 0018:ffff88881f449688 EFLAGS: 00010282
  RAX: 00000000fffffe96 RBX: ffff8881566e4460 RCX: ffffffff82079f7e
  RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffff8881566e47b0
  RBP: ffff8881566e46e0 R08: ffffed102619235d R09: ffffed102619235d
  R10: ffff888130c91ae3 R11: ffffed102619235c R12: ffff88881f4498a0
  R13: 0000000000000056 R14: 0000000000000009 R15: ffff888130c91ac0
  FS:  00007fec2cbb9700(0000) GS:ffff88881f440000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007fec1b060d80 CR3: 00000003acf94005 CR4: 00000000003706e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   <IRQ>
   tcp_try_coalesce+0xeb/0x290
   ? tcp_parse_options+0x610/0x610
   ? mark_held_locks+0x79/0xa0
   tcp_queue_rcv+0x69/0x2f0
   tcp_rcv_established+0xa49/0xd40
   ? tcp_data_queue+0x18a0/0x18a0
   tcp_v6_do_rcv+0x1c9/0x880
   ? rt6_mtu_change_route+0x100/0x100
   tcp_v6_rcv+0x1624/0x1830
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Track skbs with only zerocopy data and avoid charging them to kernel
memory to correctly account the memory utilization for msg_zerocopy.
All of the data in such skbs is held in user pages which are already
accounted to user. Before this change, they are charged again in
kernel in __zerocopy_sg_from_iter. The charging in kernel is
excessive because data is not being copied into skb frags. This
excessive charging can lead to kernel going into memory pressure
state which impacts all sockets in the system adversely. Mark pure
zerocopy skbs with a SKBFL_PURE_ZEROCOPY flag and remove
charge/uncharge for data in such skbs.

Initially, an skb is marked pure zerocopy when it is empty and in
zerocopy path. skb can then change from a pure zerocopy skb to mixed
data skb (zerocopy and copy data) if it is at tail of write queue and
there is room available in it and non-zerocopy data is being sent in
the next sendmsg call. At this time sk_mem_charge is done for the pure
zerocopied data and the pure zerocopy flag is unmarked. We found that
this happens very rarely on workloads that pass MSG_ZEROCOPY.

A pure zerocopy skb can later be coalesced into normal skb if they are
next to each other in queue but this patch prevents coalescing from
happening. This avoids complexity of charging when skb downgrades from
pure zerocopy to mixed. This is also rare.

In sk_wmem_free_skb, if it is a pure zerocopy skb, an sk_mem_uncharge
for SKB_TRUESIZE(MAX_TCP_HEADER) is done for sk_mem_charge in
tcp_skb_entail for an skb without data.

Testing with the msg_zerocopy.c benchmark between two hosts(100G nics)
with zerocopy showed that before this patch the 'sock' variable in
memory.stat for cgroup2 that tracks sum of sk_forward_alloc,
sk_rmem_alloc and sk_wmem_queued is around 1822720 and with this
change it is 0. This is due to no charge to sk_forward_alloc for
zerocopy data and shows memory utilization for kernel is lowered.
Signed-off-by: NTalal Ahmad <talalahmad@google.com>
Acked-by: NArjun Roy <arjunroy@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

This change adds a new skb extension for MCTP, to represent a
request/response flow.

The intention is to use this in a later change to allow i2c controllers
to correctly configure a multiplexer over a flow.

Since we have a cleanup function in the core path (if an extension is
present), we'll need to make CONFIG_MCTP a bool, rather than a tristate.

Includes a fix for a build warning with clang:
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NJeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Support classifying packets with netfilter on egress to satisfy user
requirements such as:
* outbound security policies for containers (Laura)
* filtering and mangling intra-node Direct Server Return (DSR) traffic
  on a load balancer (Laura)
* filtering locally generated traffic coming in through AF_PACKET,
  such as local ARP traffic generated for clustering purposes or DHCP
  (Laura; the AF_PACKET plumbing is contained in a follow-up commit)
* L2 filtering from ingress and egress for AVB (Audio Video Bridging)
  and gPTP with nftables (Pablo)
* in the future: in-kernel NAT64/NAT46 (Pablo)

The egress hook introduced herein complements the ingress hook added by
commit e687ad60 ("netfilter: add netfilter ingress hook after
handle_ing() under unique static key").  A patch for nftables to hook up
egress rules from user space has been submitted separately, so users may
immediately take advantage of the feature.

Alternatively or in addition to netfilter, packets can be classified
with traffic control (tc).  On ingress, packets are classified first by
tc, then by netfilter.  On egress, the order is reversed for symmetry.
Conceptually, tc and netfilter can be thought of as layers, with
netfilter layered above tc.

Traffic control is capable of redirecting packets to another interface
(man 8 tc-mirred).  E.g., an ingress packet may be redirected from the
host namespace to a container via a veth connection:
tc ingress (host) -> tc egress (veth host) -> tc ingress (veth container)

In this case, netfilter egress classifying is not performed when leaving
the host namespace!  That's because the packet is still on the tc layer.
If tc redirects the packet to a physical interface in the host namespace
such that it leaves the system, the packet is never subjected to
netfilter egress classifying.  That is only logical since it hasn't
passed through netfilter ingress classifying either.

Packets can alternatively be redirected at the netfilter layer using
nft fwd.  Such a packet *is* subjected to netfilter egress classifying
since it has reached the netfilter layer.

Internally, the skb->nf_skip_egress flag controls whether netfilter is
invoked on egress by __dev_queue_xmit().  Because __dev_queue_xmit() may
be called recursively by tunnel drivers such as vxlan, the flag is
reverted to false after sch_handle_egress().  This ensures that
netfilter is applied both on the overlay and underlying network.

Interaction between tc and netfilter is possible by setting and querying
skb->mark.

If netfilter egress classifying is not enabled on any interface, it is
patched out of the data path by way of a static_key and doesn't make a
performance difference that is discernible from noise:

Before:             1537 1538 1538 1537 1538 1537 Mb/sec
After:              1536 1534 1539 1539 1539 1540 Mb/sec
Before + tc accept: 1418 1418 1418 1419 1419 1418 Mb/sec
After  + tc accept: 1419 1424 1418 1419 1422 1420 Mb/sec
Before + tc drop:   1620 1619 1619 1619 1620 1620 Mb/sec
After  + tc drop:   1616 1624 1625 1624 1622 1619 Mb/sec

When netfilter egress classifying is enabled on at least one interface,
a minimal performance penalty is incurred for every egress packet, even
if the interface it's transmitted over doesn't have any netfilter egress
rules configured.  That is caused by checking dev->nf_hooks_egress
against NULL.

Measurements were performed on a Core i7-3615QM.  Commands to reproduce:
ip link add dev foo type dummy
ip link set dev foo up
modprobe pktgen
echo "add_device foo" > /proc/net/pktgen/kpktgend_3
samples/pktgen/pktgen_bench_xmit_mode_queue_xmit.sh -i foo -n 400000000 -m "11:11:11:11:11:11" -d 1.1.1.1

Accept all traffic with tc:
tc qdisc add dev foo clsact
tc filter add dev foo egress bpf da bytecode '1,6 0 0 0,'

Drop all traffic with tc:
tc qdisc add dev foo clsact
tc filter add dev foo egress bpf da bytecode '1,6 0 0 2,'

Apply this patch when measuring packet drops to avoid errors in dmesg:
https://lore.kernel.org/netdev/a73dda33-57f4-95d8-ea51-ed483abd6a7a@iogearbox.net/Signed-off-by: NLukas Wunner <lukas@wunner.de>
Cc: Laura García Liébana <nevola@gmail.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

syzbot reported another data-race in af_unix [1]

Lets change __skb_insert() to use WRITE_ONCE() when changing
skb head qlen.

Also, change unix_dgram_poll() to use lockless version
of unix_recvq_full()

It is verry possible we can switch all/most unix_recvq_full()
to the lockless version, this will be done in a future kernel version.

[1] HEAD commit: 8596e589

BUG: KCSAN: data-race in skb_queue_tail / unix_dgram_poll

write to 0xffff88814eeb24e0 of 4 bytes by task 25815 on cpu 0:
 __skb_insert include/linux/skbuff.h:1938 [inline]
 __skb_queue_before include/linux/skbuff.h:2043 [inline]
 __skb_queue_tail include/linux/skbuff.h:2076 [inline]
 skb_queue_tail+0x80/0xa0 net/core/skbuff.c:3264
 unix_dgram_sendmsg+0xff2/0x1600 net/unix/af_unix.c:1850
 sock_sendmsg_nosec net/socket.c:703 [inline]
 sock_sendmsg net/socket.c:723 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2392
 ___sys_sendmsg net/socket.c:2446 [inline]
 __sys_sendmmsg+0x315/0x4b0 net/socket.c:2532
 __do_sys_sendmmsg net/socket.c:2561 [inline]
 __se_sys_sendmmsg net/socket.c:2558 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2558
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88814eeb24e0 of 4 bytes by task 25834 on cpu 1:
 skb_queue_len include/linux/skbuff.h:1869 [inline]
 unix_recvq_full net/unix/af_unix.c:194 [inline]
 unix_dgram_poll+0x2bc/0x3e0 net/unix/af_unix.c:2777
 sock_poll+0x23e/0x260 net/socket.c:1288
 vfs_poll include/linux/poll.h:90 [inline]
 ep_item_poll fs/eventpoll.c:846 [inline]
 ep_send_events fs/eventpoll.c:1683 [inline]
 ep_poll fs/eventpoll.c:1798 [inline]
 do_epoll_wait+0x6ad/0xf00 fs/eventpoll.c:2226
 __do_sys_epoll_wait fs/eventpoll.c:2238 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2233 [inline]
 __x64_sys_epoll_wait+0xf6/0x120 fs/eventpoll.c:2233
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000001b -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25834 Comm: syz-executor.1 Tainted: G        W         5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: 86b18aaa ("skbuff: fix a data race in skb_queue_len()")
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, page->pp is cleared and set everytime the page
is recycled, which is unnecessary.

So only set the page->pp when the page is added to the page
pool and only clear it when the page is released from the
page pool.

This is also a preparation to support allocating frag page
in page pool.
Reviewed-by: NIlias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Like skb_realloc_headroom(), new helper increases headroom of specified skb.
Unlike skb_realloc_headroom(), it does not allocate a new skb if possible;
copies skb->sk on new skb when as needed and frees original skb in case
of failures.

This helps to simplify ip[6]_finish_output2() and a few other similar cases.
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If skb_dst_set_noref() is invoked with a NULL dst, the 'slow_gro'
field is cleared, too. That could lead to wrong behavior if
the skb later enters the GRO stage.

Fix the potential issue replacing preserving a non-zero value of
the 'slow_gro' field.

Additionally, fix a comment typo.
Reported-by: NSabrina Dubroca <sd@queasysnail.net>
Reported-by: NJakub Kicinski <kuba@kernel.org>
Fixes: 8a886b14 ("sk_buff: track dst status in slow_gro")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/aa42529252dc8bb02bd42e8629427040d1058537.1627662501.git.pabeni@redhat.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

Similar to the previous patch, but covering the dst field:
the slow_gro flag is additionally set when a dst is attached
to the skb

RFC -> v1:
 - use the existing flag instead of adding a new one
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The new flag tracks if any state field is set, so that
GRO requires 'unusual'/slow prepare steps.

Set such flag when a ct entry is attached to the skb,
and never clear it.

The new bit uses an existing hole into the sk_buff struct

RFC -> v1:
 - use a single state bit, never clear it
 - avoid moving the _nfct field
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change implements CPUMAP redirect support for generic XDP programs.
The idea is to reuse the cpu map entry's queue that is used to push
native xdp frames for redirecting skb to a different CPU. This will
match native XDP behavior (in that RPS is invoked again for packet
reinjected into networking stack).

To be able to determine whether the incoming skb is from the driver or
cpumap, we reuse skb->redirected bit that skips generic XDP processing
when it is set. To always make use of this, CONFIG_NET_REDIRECT guard on
it has been lifted and it is always available.

>From the redirect side, we add the skb to ptr_ring with its lowest bit
set to 1.  This should be safe as skb is not 1-byte aligned. This allows
kthread to discern between xdp_frames and sk_buff. On consumption of the
ptr_ring item, the lowest bit is unset.

In the end, the skb is simply added to the list that kthread is anyway
going to maintain for xdp_frames converted to skb, and then received
again by using netif_receive_skb_list.

Bulking optimization for generic cpumap is left as an exercise for a
future patch for now.

Since cpumap entry progs are now supported, also remove check in
generic_xdp_install for the cpumap.
Signed-off-by: NKumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NToke Høiland-Jørgensen <toke@redhat.com>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/20210702111825.491065-4-memxor@gmail.com

Up to now several high speed NICs have custom mechanisms of recycling
the allocated memory they use for their payloads.
Our page_pool API already has recycling capabilities that are always
used when we are running in 'XDP mode'. So let's tweak the API and the
kernel network stack slightly and allow the recycling to happen even
during the standard operation.
The API doesn't take into account 'split page' policies used by those
drivers currently, but can be extended once we have users for that.

The idea is to be able to intercept the packet on skb_release_data().
If it's a buffer coming from our page_pool API recycle it back to the
pool for further usage or just release the packet entirely.

To achieve that we introduce a bit in struct sk_buff (pp_recycle:1) and
a field in struct page (page->pp) to store the page_pool pointer.
Storing the information in page->pp allows us to recycle both SKBs and
their fragments.
We could have skipped the skb bit entirely, since identical information
can bederived from struct page. However, in an effort to affect the free path
as less as possible, reading a single bit in the skb which is already
in cache, is better that trying to derive identical information for the
page stored data.

The driver or page_pool has to take care of the sync operations on it's own
during the buffer recycling since the buffer is, after opting-in to the
recycling, never unmapped.

Since the gain on the drivers depends on the architecture, we are not
enabling recycling by default if the page_pool API is used on a driver.
In order to enable recycling the driver must call skb_mark_for_recycle()
to store the information we need for recycling in page->pp and
enabling the recycling bit, or page_pool_store_mem_info() for a fragment.
Co-developed-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Co-developed-by: NMatteo Croce <mcroce@microsoft.com>
Signed-off-by: NMatteo Croce <mcroce@microsoft.com>
Signed-off-by: NIlias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a prerequisite patch, the next one is enabling recycling of
skbs and fragments. Add an extra argument on __skb_frag_unref() to
handle recycling, and update the current users of the function with that.
Signed-off-by: NMatteo Croce <mcroce@microsoft.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We only have skb_send_sock_locked() which requires callers
to use lock_sock(). Introduce a variant skb_send_sock()
which locks on its own, callers do not need to lock it
any more. This will save us from adding a ->sendmsg_locked
for each protocol.

To reuse the code, pass function pointers to __skb_send_sock()
and build skb_send_sock() and skb_send_sock_locked() on top.
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NJakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-4-xiyou.wangcong@gmail.com

When openvswitch conntrack offload with act_ct action. The first rule
do conntrack in the act_ct in tc subsystem. And miss the next rule in
the tc and fallback to the ovs datapath but miss set post_ct flag
which will lead the ct_state_key with -trk flag.

Fixes: 7baf2429 ("net/sched: cls_flower add CT_FLAGS_INVALID flag support")
Signed-off-by: Nwenxu <wenxu@ucloud.cn>
Reviewed-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

{,__}skb_header_pointer() helpers exist mainly for preventing
accesses-beyond-end of the linear data.
In the vast majorify of cases, they bail out on the first condition.
All code going after is mostly a fallback.
Mark the most common branch as 'likely' one to move it in-line.
Also, skb_copy_bits() can return negative values only when the input
arguments are invalid, e.g. offset is greater than skb->len. It can
be safely marked as 'unlikely' branch, assuming that hotpath code
provides sane input to not fail here.

These two bump the throughput with a single Flow Dissector pass on
every packet (e.g. with RPS or driver that uses eth_get_headlen())
on 20 Mbps per flow/core.
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Flow Dissector code never modifies the input buffer, neither skb nor
raw data.
Make 'data' argument const for all of the Flow dissector's functions.
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function never modifies the input buffer, so 'data' argument
can be marked as const.
This implies one harmless cast-away.
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Jakub and Neil reported an increase of RTO timers whenever
TX completions are delayed a bit more (by increasing
NIC TX coalescing parameters)

Main issue is that TCP stack has a logic preventing a packet
being retransmit if the prior clone has not yet been
orphaned or freed.

This logic came with commit 1f3279ae ("tcp: avoid
retransmits of TCP packets hanging in host queues")

Thankfully, in the case skb_still_in_host_queue() detects
the initial clone is still in flight, it can use TSQ logic
that will eventually retry later, at the moment the clone
is freed or orphaned.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NNeil Spring <ntspring@fb.com>
Reported-by: NJakub Kicinski <kuba@kernel.org>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This should fix the following warning:

include/linux/skbuff.h:932: warning: Function parameter or member
'_sk_redir' not described in 'sk_buff'
Reported-by: NLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Acked-by: NLorenz Bauer <lmb@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210301184805.8174-1-xiyou.wangcong@gmail.com

Currently TCP_SKB_CB() is hard-coded in skmsg code, it certainly
does not work for any other non-TCP protocols. We can move them to
skb ext, but it introduces a memory allocation on fast path.

Fortunately, we only need to a word-size to store all the information,
because the flags actually only contains 1 bit so can be just packed
into the lowest bit of the "pointer", which is stored as unsigned
long.

Inside struct sk_buff, '_skb_refdst' can be reused because skb dst is
no longer needed after ->sk_data_ready() so we can just drop it.
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Acked-by: NJakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210223184934.6054-5-xiyou.wangcong@gmail.com

napi_frags_finish() and napi_skb_finish() can only be called inside
NAPI Rx context, so we can feed NAPI cache with skbuff_heads that
got NAPI_MERGED_FREE verdict instead of immediate freeing.
Replace __kfree_skb() with __kfree_skb_defer() in napi_skb_finish()
and move napi_skb_free_stolen_head() to skbuff.c, so it can drop skbs
to NAPI cache.
As many drivers call napi_alloc_skb()/napi_get_frags() on their
receive path, this becomes especially useful.
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Instead of just bulk-flushing skbuff_heads queued up through
napi_consume_skb() or __kfree_skb_defer(), try to reuse them
on allocation path.
If the cache is empty on allocation, bulk-allocate the first
16 elements, which is more efficient than per-skb allocation.
If the cache is full on freeing, bulk-wipe the second half of
the cache (32 elements).
This also includes custom KASAN poisoning/unpoisoning to be
double sure there are no use-after-free cases.

To not change current behaviour, introduce a new function,
napi_build_skb(), to optionally use a new approach later
in drivers.

Note on selected bulk size, 16:
 - this equals to XDP_BULK_QUEUE_SIZE, DEV_MAP_BULK_SIZE
   and especially VETH_XDP_BATCH, which is also used to
   bulk-allocate skbuff_heads and was tested on powerful
   setups;
 - this also showed the best performance in the actual
   test series (from the array of {8, 16, 32}).

Suggested-by: Edward Cree <ecree.xilinx@gmail.com> # Divide on two halves
Suggested-by: Eric Dumazet <edumazet@google.com>   # KASAN poisoning
Cc: Dmitry Vyukov <dvyukov@google.com>             # Help with KASAN
Cc: Paolo Abeni <pabeni@redhat.com>                # Reduced batch size
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This function isn't much needed as NAPI skb queue gets bulk-freed
anyway when there's no more room, and even may reduce the efficiency
of bulk operations.
It will be even less needed after reusing skb cache on allocation path,
so remove it and this way lighten network softirqs a bit.
Suggested-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the current implementation of {netdev,napi}_alloc_frag(), it doesn't
have any align guarantee for the returned buffer address, But for some
hardwares they do require the DMA buffer to be aligned correctly,
so we would have to use some workarounds like below if the buffers
allocated by the {netdev,napi}_alloc_frag() are used by these hardwares
for DMA.
    buf = napi_alloc_frag(really_needed_size + align);
    buf = PTR_ALIGN(buf, align);

These codes seems ugly and would waste a lot of memories if the buffers
are used in a network driver for the TX/RX. We have added the align
support for the page_frag functions, so add the corresponding
{netdev,napi}_frag functions.
Signed-off-by: NKevin Hao <haokexin@gmail.com>
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

A bunch of drivers test the page before reusing/recycling for two
common conditions:
 - if a page was allocated under memory pressure (pfmemalloc page);
 - if a page was allocated at a distant memory node (to exclude
   slowdowns).

Introduce a new common inline for doing this, with likely() already
folded inside to make driver code a bit simpler.
Suggested-by: NDavid Rientjes <rientjes@google.com>
Suggested-by: NJakub Kicinski <kuba@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Reviewed-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

The function doesn't write anything to the page struct itself,
so this argument can be const.

Misc: align second argument to the brace while at it.
Signed-off-by: NAlexander Lobakin <alobakin@pm.me>
Reviewed-by: NJesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

This patch adds TCP_NLA_TTL to SCM_TIMESTAMPING_OPT_STATS that exports
the time-to-live or hop limit of the latest incoming packet with
SCM_TSTAMP_ACK. The value exported may not be from the packet that acks
the sequence when incoming packets are aggregated. Exporting the
time-to-live or hop limit value of incoming packets helps to estimate
the hop count of the path of the flow that may change over time.
Signed-off-by: NYousuk Seung <ysseung@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Link: https://lore.kernel.org/r/20210120204155.552275-1-ysseung@google.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

This patch add the TCA_FLOWER_KEY_CT_FLAGS_INVALID flag to
match the ct_state with invalid for conntrack.
Signed-off-by: Nwenxu <wenxu@ucloud.cn>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://lore.kernel.org/r/1611045110-682-1-git-send-email-wenxu@ucloud.cnSigned-off-by: NJakub Kicinski <kuba@kernel.org>

This patch is to define a inline function skb_csum_is_sctp(), and
also replace all places where it checks if it's a SCTP CSUM skb.
This function would be used later in many networking drivers in
the following patches.
Suggested-by: NAlexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

skb_seq_read iterates over an skb, returning pointer and length of
the next data range with each call.

It relies on kmap_atomic to access highmem pages when needed.

An skb frag may be backed by a compound page, but kmap_atomic maps
only a single page. There are not enough kmap slots to always map all
pages concurrently.

Instead, if kmap_atomic is needed, iterate over each page.

As this increases the number of calls, avoid this unless needed.
The necessary condition is captured in skb_frag_must_loop.

I tried to make the change as obvious as possible. It should be easy
to verify that nothing changes if skb_frag_must_loop returns false.

Tested:
  On an x86 platform with
    CONFIG_HIGHMEM=y
    CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP=y
    CONFIG_NETFILTER_XT_MATCH_STRING=y

  Run
    ip link set dev lo mtu 1500
    iptables -A OUTPUT -m string --string 'badstring' -algo bm -j ACCEPT
    dd if=/dev/urandom of=in bs=1M count=20
    nc -l -p 8000 > /dev/null &
    nc -w 1 -q 0 localhost 8000 < in
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Skb frags may be backed by highmem and/or compound pages. Highmem
pages need kmap_atomic mappings to access. But kmap_atomic maps a
single page, not the entire compound page.

skb_foreach_page iterates over an skb frag, in one step in the common
case, page by page only if kmap_atomic must be called for each page.
The decision logic is captured in skb_frag_must_loop.

CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP extends kmap from highmem to all
pages, to increase code coverage.

Extend skb_frag_must_loop to this new condition.

Link: https://lore.kernel.org/linux-mm/20210106180132.41dc249d@gandalf.local.home/
Fixes: 0e91a0c6 ("mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP")
Reported-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Tested-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Unlike the rest of the skb_zcopy_ functions, these routines
operate on a 'struct ubuf', not a skb.  Remove the 'skb_'
prefix from the naming to make things clearer.
Suggested-by: NWillem de Bruijn <willemdebruijn.kernel@gmail.com>
Signed-off-by: NJonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>