tcp: Clear req->syncookie in reqsk_alloc().

syzkaller reported a read of uninit req->syncookie. [0]

Originally, req->syncookie was used only in tcp_conn_request()
to indicate if we need to encode SYN cookie in SYN+ACK, so the
field remains uninitialised in other places.

The commit 695751e31a63 ("bpf: tcp: Handle BPF SYN Cookie in
cookie_v[46]_check().") added another meaning in ACK path;
req->syncookie is set true if SYN cookie is validated by BPF
kfunc.

After the change, cookie_v[46]_check() always read req->syncookie,
but it is not initialised in the normal SYN cookie case as reported
by KMSAN.

Let's make sure we always initialise req->syncookie in reqsk_alloc().

[0]:
BUG: KMSAN: uninit-value in cookie_v4_check+0x22b7/0x29e0
net/ipv4/syncookies.c:477
cookie_v4_check+0x22b7/0x29e0 net/ipv4/syncookies.c:477
tcp_v4_cookie_check net/ipv4/tcp_ipv4.c:1855 [inline]
tcp_v4_do_rcv+0xb17/0x10b0 net/ipv4/tcp_ipv4.c:1914
tcp_v4_rcv+0x4ce4/0x5420 net/ipv4/tcp_ipv4.c:2322
ip_protocol_deliver_rcu+0x2a3/0x13d0 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x332/0x500 net/ipv4/ip_input.c:233
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254
dst_input include/net/dst.h:460 [inline]
ip_rcv_finish+0x4a2/0x520 net/ipv4/ip_input.c:449
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_rcv+0xcd/0x380 net/ipv4/ip_input.c:569
__netif_receive_skb_one_core net/core/dev.c:5538 [inline]
__netif_receive_skb+0x319/0x9e0 net/core/dev.c:5652
process_backlog+0x480/0x8b0 net/core/dev.c:5981
__napi_poll+0xe7/0x980 net/core/dev.c:6632
napi_poll net/core/dev.c:6701 [inline]
net_rx_action+0x89d/0x1820 net/core/dev.c:6813
__do_softirq+0x1c0/0x7d7 kernel/softirq.c:554
do_softirq+0x9a/0x100 kernel/softirq.c:455
__local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:382
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:820 [inline]
__dev_queue_xmit+0x2776/0x52c0 net/core/dev.c:4362
dev_queue_xmit include/linux/netdevice.h:3091 [inline]
neigh_hh_output include/net/neighbour.h:526 [inline]
neigh_output include/net/neighbour.h:540 [inline]
ip_finish_output2+0x187a/0x1b70 net/ipv4/ip_output.c:235
__ip_finish_output+0x287/0x810
ip_finish_output+0x4b/0x550 net/ipv4/ip_output.c:323
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip_output+0x15f/0x3f0 net/ipv4/ip_output.c:433
dst_output include/net/dst.h:450 [inline]
ip_local_out net/ipv4/ip_output.c:129 [inline]
__ip_queue_xmit+0x1e93/0x2030 net/ipv4/ip_output.c:535
ip_queue_xmit+0x60/0x80 net/ipv4/ip_output.c:549
__tcp_transmit_skb+0x3c70/0x4890 net/ipv4/tcp_output.c:1462
tcp_transmit_skb net/ipv4/tcp_output.c:1480 [inline]
tcp_write_xmit+0x3ee1/0x8900 net/ipv4/tcp_output.c:2792
__tcp_push_pending_frames net/ipv4/tcp_output.c:2977 [inline]
tcp_send_fin+0xa90/0x12e0 net/ipv4/tcp_output.c:3578
tcp_shutdown+0x198/0x1f0 net/ipv4/tcp.c:2716
inet_shutdown+0x33f/0x5b0 net/ipv4/af_inet.c:923
__sys_shutdown_sock net/socket.c:2425 [inline]
__sys_shutdown net/socket.c:2437 [inline]
__do_sys_shutdown net/socket.c:2445 [inline]
__se_sys_shutdown+0x2a4/0x440 net/socket.c:2443
__x64_sys_shutdown+0x6c/0xa0 net/socket.c:2443
do_syscall_64+0xd5/0x1f0
entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was stored to memory at:
reqsk_alloc include/net/request_sock.h:148 [inline]
inet_reqsk_alloc+0x651/0x7a0 net/ipv4/tcp_input.c:6978
cookie_tcp_reqsk_alloc+0xd4/0x900 net/ipv4/syncookies.c:328
cookie_tcp_check net/ipv4/syncookies.c:388 [inline]
cookie_v4_check+0x289f/0x29e0 net/ipv4/syncookies.c:420
tcp_v4_cookie_check net/ipv4/tcp_ipv4.c:1855 [inline]
tcp_v4_do_rcv+0xb17/0x10b0 net/ipv4/tcp_ipv4.c:1914
tcp_v4_rcv+0x4ce4/0x5420 net/ipv4/tcp_ipv4.c:2322
ip_protocol_deliver_rcu+0x2a3/0x13d0 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x332/0x500 net/ipv4/ip_input.c:233
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254
dst_input include/net/dst.h:460 [inline]
ip_rcv_finish+0x4a2/0x520 net/ipv4/ip_input.c:449
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_rcv+0xcd/0x380 net/ipv4/ip_input.c:569
__netif_receive_skb_one_core net/core/dev.c:5538 [inline]
__netif_receive_skb+0x319/0x9e0 net/core/dev.c:5652
process_backlog+0x480/0x8b0 net/core/dev.c:5981
__napi_poll+0xe7/0x980 net/core/dev.c:6632
napi_poll net/core/dev.c:6701 [inline]
net_rx_action+0x89d/0x1820 net/core/dev.c:6813
__do_softirq+0x1c0/0x7d7 kernel/softirq.c:554

Uninit was created at:
__alloc_pages+0x9a7/0xe00 mm/page_alloc.c:4592
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page mm/slub.c:2175 [inline]
allocate_slab mm/slub.c:2338 [inline]
new_slab+0x2de/0x1400 mm/slub.c:2391
___slab_alloc+0x1184/0x33d0 mm/slub.c:3525
__slab_alloc mm/slub.c:3610 [inline]
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
kmem_cache_alloc+0x6d3/0xbe0 mm/slub.c:3852
reqsk_alloc include/net/request_sock.h:131 [inline]
inet_reqsk_alloc+0x66/0x7a0 net/ipv4/tcp_input.c:6978
tcp_conn_request+0x484/0x44e0 net/ipv4/tcp_input.c:7135
tcp_v4_conn_request+0x16f/0x1d0 net/ipv4/tcp_ipv4.c:1716
tcp_rcv_state_process+0x2e5/0x4bb0 net/ipv4/tcp_input.c:6655
tcp_v4_do_rcv+0xbfd/0x10b0 net/ipv4/tcp_ipv4.c:1929
tcp_v4_rcv+0x4ce4/0x5420 net/ipv4/tcp_ipv4.c:2322
ip_protocol_deliver_rcu+0x2a3/0x13d0 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x332/0x500 net/ipv4/ip_input.c:233
NF_HOOK include/linux/netfilter.h:314 [inline]
ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254
dst_input include/net/dst.h:460 [inline]
ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline]
ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline]
ip_sublist_rcv+0x15f3/0x17f0 net/ipv4/ip_input.c:639
ip_list_rcv+0x9ef/0xa40 net/ipv4/ip_input.c:674
__netif_receive_skb_list_ptype net/core/dev.c:5581 [inline]
__netif_receive_skb_list_core+0x15c5/0x1670 net/core/dev.c:5629
__netif_receive_skb_list net/core/dev.c:5681 [inline]
netif_receive_skb_list_internal+0x106c/0x16f0 net/core/dev.c:5773
gro_normal_list include/net/gro.h:438 [inline]
napi_complete_done+0x425/0x880 net/core/dev.c:6113
virtqueue_napi_complete drivers/net/virtio_net.c:465 [inline]
virtnet_poll+0x149d/0x2240 drivers/net/virtio_net.c:2211
__napi_poll+0xe7/0x980 net/core/dev.c:6632
napi_poll net/core/dev.c:6701 [inline]
net_rx_action+0x89d/0x1820 net/core/dev.c:6813
__do_softirq+0x1c0/0x7d7 kernel/softirq.c:554

CPU: 0 PID: 16792 Comm: syz-executor.2 Not tainted 6.8.0-syzkaller-05562-g61387b8dcf1d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024

Fixes: 695751e31a63 ("bpf: tcp: Handle BPF SYN Cookie in cookie_v[46]_check().")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Closes: https://lore.kernel.org/bpf/CANn89iKdN9c+C_2JAUbc+VY3DDQjAQukMtiBbormAmAk9CdvQA@mail.gmail.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240315224710.55209-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

bpf: tcp: Handle BPF SYN Cookie in skb_steal_sock().

We will support arbitrary SYN Cookie with BPF.

If BPF prog validates ACK and kfunc allocates a reqsk, it will
be carried to TCP stack as skb->sk with req->syncookie 1. Also,
the reqsk has its listener as req->rsk_listener with no refcnt
taken.

When the TCP stack looks up a socket from the skb, we steal
inet_reqsk(skb->sk)->rsk_listener in skb_steal_sock() so that
the skb will be processed in cookie_v[46]_check() with the
listener.

Note that we do not clear skb->sk and skb->destructor so that we
can carry the reqsk to cookie_v[46]_check().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240115205514.68364-4-kuniyu@amazon.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tcp: Move skb_steal_sock() to request_sock.h

We will support arbitrary SYN Cookie with BPF.

If BPF prog validates ACK and kfunc allocates a reqsk, it will
be carried to TCP stack as skb->sk with req->syncookie 1.

In skb_steal_sock(), we need to check inet_reqsk(sk)->syncookie
to see if the reqsk is created by kfunc. However, inet_reqsk()
is not available in sock.h.

Let's move skb_steal_sock() to request_sock.h.

While at it, we refactor skb_steal_sock() so it returns early if
skb->sk is NULL to minimise the following patch.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240115205514.68364-3-kuniyu@amazon.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tcp: Use BPF timeout setting for SYN ACK RTO

When setting RTO through BPF program, some SYN ACK packets were unaffected
and continued to use TCP_TIMEOUT_INIT constant. This patch adds timeout
option to struct request_sock. Option is initialized with TCP_TIMEOUT_INIT
and is reassigned through BPF using tcp_timeout_init call. SYN ACK
retransmits now use newly added timeout option.

Signed-off-by: Akhmat Karakotov <hmukos@yandex-team.ru>
Acked-by: Martin KaFai Lau <kafai@fb.com>

v2:
- Add timeout option to struct request_sock. Do not call
tcp_timeout_init on every syn ack retransmit.

v3:
- Use unsigned long for min. Bound tcp_timeout_init to TCP_RTO_MAX.

v4:
- Refactor duplicate code by adding reqsk_timeout function.
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: bpf: Optionally store mac header in TCP_SAVE_SYN

This patch is adapted from Eric's patch in an earlier discussion [1].

The TCP_SAVE_SYN currently only stores the network header and
tcp header. This patch allows it to optionally store
the mac header also if the setsockopt's optval is 2.

It requires one more bit for the "save_syn" bit field in tcp_sock.
This patch achieves this by moving the syn_smc bit next to the is_mptcp.
The syn_smc is currently used with the TCP experimental option. Since
syn_smc is only used when CONFIG_SMC is enabled, this patch also puts
the "IS_ENABLED(CONFIG_SMC)" around it like the is_mptcp did
with "IS_ENABLED(CONFIG_MPTCP)".

The mac_hdrlen is also stored in the "struct saved_syn"
to allow a quick offset from the bpf prog if it chooses to start
getting from the network header or the tcp header.

[1]: https://lore.kernel.org/netdev/CANn89iLJNWh6bkH7DNhy_kmcAexuUCccqERqe7z2QsvPhGrYPQ@mail.gmail.com/

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20200820190123.2886935-1-kafai@fb.com

tcp: Use a struct to represent a saved_syn

The TCP_SAVE_SYN has both the network header and tcp header.
The total length of the saved syn packet is currently stored in
the first 4 bytes (u32) of an array and the actual packet data is
stored after that.

A later patch will add a bpf helper that allows to get the tcp header
alone from the saved syn without the network header. It will be more
convenient to have a direct offset to a specific header instead of
re-parsing it. This requires to separately store the network hdrlen.
The total header length (i.e. network + tcp) is still needed for the
current usage in getsockopt. Although this total length can be obtained
by looking into the tcphdr and then get the (th->doff << 2), this patch
chooses to directly store the tcp hdrlen in the second four bytes of
this newly created "struct saved_syn". By using a new struct, it can
give a readable name to each individual header length.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200820190014.2883694-1-kafai@fb.com

tcp: rename request_sock cookie_ts bit to syncookie

Nowadays output function has a 'synack_type' argument that tells us when
the syn/ack is emitted via syncookies.

The request already tells us when timestamps are supported, so check
both to detect special timestamp for tcp option encoding is needed.

We could remove cookie_ts altogether, but a followup patch would
otherwise need to adjust function signatures to pass 'want_cookie' to
mptcp core.

This way, the 'existing' bit can be used.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add {READ|WRITE}_ONCE() annotations on ->rskq_accept_head

reqsk_queue_empty() is called from inet_csk_listen_poll() while
other cpus might write ->rskq_accept_head value.

Use {READ|WRITE}_ONCE() to avoid compiler tricks
and potential KCSAN splats.

Fixes: fff1f3001cc5 ("tcp: add a spinlock to protect struct request_sock_queue")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

inet: clear num_timeout reqsk_alloc()

KMSAN caught uninit-value in tcp_create_openreq_child() [1]
This is caused by a recent change, combined by the fact
that TCP cleared num_timeout, num_retrans and sk fields only
when a request socket was about to be queued.

Under syncookie mode, a temporary request socket is used,
and req->num_timeout could contain garbage.

Lets clear these three fields sooner, there is really no
point trying to defer this and risk other bugs.

[1]

BUG: KMSAN: uninit-value in tcp_create_openreq_child+0x157f/0x1cc0 net/ipv4/tcp_minisocks.c:526
CPU: 1 PID: 13357 Comm: syz-executor591 Not tainted 5.2.0-rc4+ #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x191/0x1f0 lib/dump_stack.c:113
kmsan_report+0x162/0x2d0 mm/kmsan/kmsan.c:611
__msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:304
tcp_create_openreq_child+0x157f/0x1cc0 net/ipv4/tcp_minisocks.c:526
tcp_v6_syn_recv_sock+0x761/0x2d80 net/ipv6/tcp_ipv6.c:1152
tcp_get_cookie_sock+0x16e/0x6b0 net/ipv4/syncookies.c:209
cookie_v6_check+0x27e0/0x29a0 net/ipv6/syncookies.c:252
tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1039 [inline]
tcp_v6_do_rcv+0xf1c/0x1ce0 net/ipv6/tcp_ipv6.c:1344
tcp_v6_rcv+0x60b7/0x6a30 net/ipv6/tcp_ipv6.c:1554
ip6_protocol_deliver_rcu+0x1433/0x22f0 net/ipv6/ip6_input.c:397
ip6_input_finish net/ipv6/ip6_input.c:438 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_input+0x2af/0x340 net/ipv6/ip6_input.c:447
dst_input include/net/dst.h:439 [inline]
ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ipv6_rcv+0x683/0x710 net/ipv6/ip6_input.c:272
__netif_receive_skb_one_core net/core/dev.c:4981 [inline]
__netif_receive_skb net/core/dev.c:5095 [inline]
process_backlog+0x721/0x1410 net/core/dev.c:5906
napi_poll net/core/dev.c:6329 [inline]
net_rx_action+0x738/0x1940 net/core/dev.c:6395
__do_softirq+0x4ad/0x858 kernel/softirq.c:293
do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1052
</IRQ>
do_softirq kernel/softirq.c:338 [inline]
__local_bh_enable_ip+0x199/0x1e0 kernel/softirq.c:190
local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
rcu_read_unlock_bh include/linux/rcupdate.h:682 [inline]
ip6_finish_output2+0x213f/0x2670 net/ipv6/ip6_output.c:117
ip6_finish_output+0xae4/0xbc0 net/ipv6/ip6_output.c:150
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip6_output+0x5d3/0x720 net/ipv6/ip6_output.c:167
dst_output include/net/dst.h:433 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_xmit+0x1f53/0x2650 net/ipv6/ip6_output.c:271
inet6_csk_xmit+0x3df/0x4f0 net/ipv6/inet6_connection_sock.c:135
__tcp_transmit_skb+0x4076/0x5b40 net/ipv4/tcp_output.c:1156
tcp_transmit_skb net/ipv4/tcp_output.c:1172 [inline]
tcp_write_xmit+0x39a9/0xa730 net/ipv4/tcp_output.c:2397
__tcp_push_pending_frames+0x124/0x4e0 net/ipv4/tcp_output.c:2573
tcp_send_fin+0xd43/0x1540 net/ipv4/tcp_output.c:3118
tcp_close+0x16ba/0x1860 net/ipv4/tcp.c:2403
inet_release+0x1f7/0x270 net/ipv4/af_inet.c:427
inet6_release+0xaf/0x100 net/ipv6/af_inet6.c:470
__sock_release net/socket.c:601 [inline]
sock_close+0x156/0x490 net/socket.c:1273
__fput+0x4c9/0xba0 fs/file_table.c:280
____fput+0x37/0x40 fs/file_table.c:313
task_work_run+0x22e/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:185 [inline]
exit_to_usermode_loop arch/x86/entry/common.c:168 [inline]
prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:199
syscall_return_slowpath+0x90/0x5c0 arch/x86/entry/common.c:279
do_syscall_64+0xe2/0xf0 arch/x86/entry/common.c:305
entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x401d50
Code: 01 f0 ff ff 0f 83 40 0d 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d dd 8d 2d 00 00 75 14 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 14 0d 00 00 c3 48 83 ec 08 e8 7a 02 00 00
RSP: 002b:00007fff1cf58cf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000401d50
RDX: 000000000000001c RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000004a9050 R08: 0000000020000040 R09: 000000000000001c
R10: 0000000020004004 R11: 0000000000000246 R12: 0000000000402ef0
R13: 0000000000402f80 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:201 [inline]
kmsan_internal_poison_shadow+0x53/0xa0 mm/kmsan/kmsan.c:160
kmsan_kmalloc+0xa4/0x130 mm/kmsan/kmsan_hooks.c:177
kmem_cache_alloc+0x534/0xb00 mm/slub.c:2781
reqsk_alloc include/net/request_sock.h:84 [inline]
inet_reqsk_alloc+0xa8/0x600 net/ipv4/tcp_input.c:6384
cookie_v6_check+0xadb/0x29a0 net/ipv6/syncookies.c:173
tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1039 [inline]
tcp_v6_do_rcv+0xf1c/0x1ce0 net/ipv6/tcp_ipv6.c:1344
tcp_v6_rcv+0x60b7/0x6a30 net/ipv6/tcp_ipv6.c:1554
ip6_protocol_deliver_rcu+0x1433/0x22f0 net/ipv6/ip6_input.c:397
ip6_input_finish net/ipv6/ip6_input.c:438 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_input+0x2af/0x340 net/ipv6/ip6_input.c:447
dst_input include/net/dst.h:439 [inline]
ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ipv6_rcv+0x683/0x710 net/ipv6/ip6_input.c:272
__netif_receive_skb_one_core net/core/dev.c:4981 [inline]
__netif_receive_skb net/core/dev.c:5095 [inline]
process_backlog+0x721/0x1410 net/core/dev.c:5906
napi_poll net/core/dev.c:6329 [inline]
net_rx_action+0x738/0x1940 net/core/dev.c:6395
__do_softirq+0x4ad/0x858 kernel/softirq.c:293
do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1052
do_softirq kernel/softirq.c:338 [inline]
__local_bh_enable_ip+0x199/0x1e0 kernel/softirq.c:190
local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
rcu_read_unlock_bh include/linux/rcupdate.h:682 [inline]
ip6_finish_output2+0x213f/0x2670 net/ipv6/ip6_output.c:117
ip6_finish_output+0xae4/0xbc0 net/ipv6/ip6_output.c:150
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip6_output+0x5d3/0x720 net/ipv6/ip6_output.c:167
dst_output include/net/dst.h:433 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ip6_xmit+0x1f53/0x2650 net/ipv6/ip6_output.c:271
inet6_csk_xmit+0x3df/0x4f0 net/ipv6/inet6_connection_sock.c:135
__tcp_transmit_skb+0x4076/0x5b40 net/ipv4/tcp_output.c:1156
tcp_transmit_skb net/ipv4/tcp_output.c:1172 [inline]
tcp_write_xmit+0x39a9/0xa730 net/ipv4/tcp_output.c:2397
__tcp_push_pending_frames+0x124/0x4e0 net/ipv4/tcp_output.c:2573
tcp_send_fin+0xd43/0x1540 net/ipv4/tcp_output.c:3118
tcp_close+0x16ba/0x1860 net/ipv4/tcp.c:2403
inet_release+0x1f7/0x270 net/ipv4/af_inet.c:427
inet6_release+0xaf/0x100 net/ipv6/af_inet6.c:470
__sock_release net/socket.c:601 [inline]
sock_close+0x156/0x490 net/socket.c:1273
__fput+0x4c9/0xba0 fs/file_table.c:280
____fput+0x37/0x40 fs/file_table.c:313
task_work_run+0x22e/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:185 [inline]
exit_to_usermode_loop arch/x86/entry/common.c:168 [inline]
prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:199
syscall_return_slowpath+0x90/0x5c0 arch/x86/entry/common.c:279
do_syscall_64+0xe2/0xf0 arch/x86/entry/common.c:305
entry_SYSCALL_64_after_hwframe+0x63/0xe7

Fixes: 336c39a03151 ("tcp: undo init congestion window on false SYNACK timeout")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tcp: free request sock directly upon TFO or syncookies error

Since the request socket is created locally, it'd make more sense to
use reqsk_free() instead of reqsk_put() in TFO and syncookies' error
path.

However, tcp_get_cookie_sock() may set ->rsk_refcnt before freeing the
socket; tcp_conn_request() may also have non-null ->rsk_refcnt because
of tcp_try_fastopen(). In both cases 'req' hasn't been exposed
to the outside world and is safe to free immediately, but that'd
trigger the WARN_ON_ONCE in reqsk_free().

Define __reqsk_free() for these situations where we know nobody's
referencing the socket, even though ->rsk_refcnt might be non-null.
Now we can consolidate the error path of tcp_get_cookie_sock() and
tcp_conn_request().

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: keep refcount warning in reqsk_free()

As Eric Dumazet said, "We do not have a way to tell if the req was ever
inserted in a hash table, so better play safe.".
Let's remove this comment, so that nobody will be tempted to drop the
WARN_ON_ONCE() line.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: socket option to set TCP fast open key

New socket option TCP_FASTOPEN_KEY to allow different keys per
listener. The listener by default uses the global key until the
socket option is set. The key is a 16 bytes long binary data. This
option has no effect on regular non-listener TCP sockets.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: convert sock.sk_refcnt from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

This patch uses refcount_inc_not_zero() instead of
atomic_inc_not_zero_hint() due to absense of a _hint()
version of refcount API. If the hint() version must
be used, we might need to revisit API.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: make struct request_sock_ops::obj_size unsigned

This field is sizeof of corresponding kmem_cache so it can't be negative.

Space will be saved after 32-bit kmem_cache_create() patch.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Namespaceify tcp_max_syn_backlog knob

Different namespace application might require different maximal
number of remembered connection requests.

Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: reqsk_alloc() needs to take care of dead listeners

We'll soon no longer take a refcount on listeners,
so reqsk_alloc() can not assume a listener refcount is not
zero. We need to use atomic_inc_not_zero()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add inet_sk_transparent() helper

Avoids cluttering tcp_v4_send_reset when followup patch extends
it to deal with timewait sockets.

Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp/dccp: fix race at listener dismantle phase

Under stress, a close() on a listener can trigger the
WARN_ON(sk->sk_ack_backlog) in inet_csk_listen_stop()

We need to test if listener is still active before queueing
a child in inet_csk_reqsk_queue_add()

Create a common inet_child_forget() helper, and use it
from inet_csk_reqsk_queue_add() and inet_csk_listen_stop()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: shrink struct sock and request_sock by 8 bytes

One 32bit hole is following skc_refcnt, use it.
skc_incoming_cpu can also be an union for request_sock rcv_wnd.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: align sk_refcnt on 128 bytes boundary

sk->sk_refcnt is dirtied for every TCP/UDP incoming packet.
This is a performance issue if multiple cpus hit a common socket,
or multiple sockets are chained due to SO_REUSEPORT.

By moving sk_refcnt 8 bytes further, first 128 bytes of sockets
are mostly read. As they contain the lookup keys, this has
a considerable performance impact, as cpus can cache them.

These 8 bytes are not wasted, we use them as a place holder
for various fields, depending on the socket type.

Tested:
SYN flood hitting a 16 RX queues NIC.
TCP listener using 16 sockets and SO_REUSEPORT
and SO_INCOMING_CPU for proper siloing.

Could process 6.0 Mpps SYN instead of 4.2 Mpps

Kernel profile looked like :
11.68% [kernel] [k] sha_transform
6.51% [kernel] [k] __inet_lookup_listener
5.07% [kernel] [k] __inet_lookup_established
4.15% [kernel] [k] memcpy_erms
3.46% [kernel] [k] ipt_do_table
2.74% [kernel] [k] fib_table_lookup
2.54% [kernel] [k] tcp_make_synack
2.34% [kernel] [k] tcp_conn_request
2.05% [kernel] [k] __netif_receive_skb_core
2.03% [kernel] [k] kmem_cache_alloc

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: avoid two atomic ops for syncookies

inet_reqsk_alloc() is used to allocate a temporary request
in order to generate a SYNACK with a cookie. Then later,
syncookie validation also uses a temporary request.

These paths already took a reference on listener refcount,
we can avoid a couple of atomic operations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: use sk_fullsock() in __netdev_pick_tx()

SYN_RECV & TIMEWAIT sockets are not full blown, they do not have a
sk_dst_cache pointer.

Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp/dccp: add SLAB_DESTROY_BY_RCU flag for request sockets

Before letting request sockets being put in TCP/DCCP regular
ehash table, we need to add either :

- SLAB_DESTROY_BY_RCU flag to their kmem_cache
- add RCU grace period before freeing them.

Since we carefully respected the SLAB_DESTROY_BY_RCU protocol
like ESTABLISH and TIMEWAIT sockets, use it here.

req_prot_init() being only used by TCP and DCCP, I did not add
a new slab_flags into their rsk_prot, but reuse prot->slab_flags

Since all reqsk_alloc() users are correctly dealing with a failure,
add the __GFP_NOWARN flag to avoid traces under pressure.

Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: remove max_qlen_log

This control variable was set at first listen(fd, backlog)
call, but not updated if application tried to increase or decrease
backlog. It made sense at the time listener had a non resizeable
hash table.

Also rounding to powers of two was not very friendly.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp/dccp: remove struct listen_sock

It is enough to check listener sk_state, no need for an extra
condition.

max_qlen_log can be moved into struct request_sock_queue

We can remove syn_wait_lock and the alignment it enforced.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp/dccp: shrink struct listen_sock

We no longer use hash_rnd, nr_table_entries and syn_table[]

For a listener with a backlog of 10 millions sockets, this
saves 80 MBytes of vmalloced memory.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp/dccp: install syn_recv requests into ehash table

In this patch, we insert request sockets into TCP/DCCP
regular ehash table (where ESTABLISHED and TIMEWAIT sockets
are) instead of using the per listener hash table.

ACK packets find SYN_RECV pseudo sockets without having
to find and lock the listener.

In nominal conditions, this halves pressure on listener lock.

Note that this will allow for SO_REUSEPORT refinements,
so that we can select a listener using cpu/numa affinities instead
of the prior 'consistent hash', since only SYN packets will
apply this selection logic.

We will shrink listen_sock in the following patch to ease
code review.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ying Cai <ycai@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp/dccp: init sk_prot and call sk_node_init() in reqsk_alloc()

We plan to use generic functions to insert request sockets
into ehash table.

sk_prot needs to be set (to retrieve sk_prot->h.hashinfo)
sk_node needs to be cleared.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: move synflood_warned into struct request_sock_queue

long term plan is to remove struct listen_sock when its hash
table is no longer there.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: move qlen/young out of struct listen_sock

qlen_inc & young_inc were protected by listener lock,
while qlen_dec & young_dec were atomic fields.

Everything needs to be atomic for upcoming lockless listener.

Also move qlen/young in request_sock_queue as we'll get rid
of struct listen_sock eventually.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: add a spinlock to protect struct request_sock_queue

struct request_sock_queue fields are currently protected
by the listener 'lock' (not a real spinlock)

We need to add a private spinlock instead, so that softirq handlers
creating children do not have to worry with backlog notion
that the listener 'lock' carries.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: prepare fastopen code for upcoming listener changes

While auditing TCP stack for upcoming 'lockless' listener changes,
I found I had to change fastopen_init_queue() to properly init the object
before publishing it.

Otherwise an other cpu could try to lock the spinlock before it gets
properly initialized.

Instead of adding appropriate barriers, just remove dynamic memory
allocations :
- Structure is 28 bytes on 64bit arches. Using additional 8 bytes
for holding a pointer seems overkill.
- Two listeners can share same cache line and performance would suffer.

If we really want to save few bytes, we would instead dynamically allocate
whole struct request_sock_queue in the future.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: constify tcp_syn_flood_action() socket argument

tcp_syn_flood_action() will soon be called with unlocked socket.
In order to avoid SYN flood warning being emitted multiple times,
use xchg().
Extend max_qlen_log and synflood_warned fields in struct listen_sock
to u32

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp/dccp: constify send_synack and send_reset socket argument

None of these functions need to change the socket, make it
const.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: constify inet_rtx_syn_ack() sock argument

SYNACK packets are sent on behalf on unlocked listeners
or fastopen sockets. Mark socket as const to catch future changes
that might break the assumption.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp/dccp: constify rtx_synack() and friends

This is done to make sure we do not change listener socket
while sending SYNACK packets while socket lock is not held.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: provide SYN headers for passive connections

This patch allows a server application to get the TCP SYN headers for
its passive connections. This is useful if the server is doing
fingerprinting of clients based on SYN packet contents.

Two socket options are added: TCP_SAVE_SYN and TCP_SAVED_SYN.

The first is used on a socket to enable saving the SYN headers
for child connections. This can be set before or after the listen()
call.

The latter is used to retrieve the SYN headers for passive connections,
if the parent listener has enabled TCP_SAVE_SYN.

TCP_SAVED_SYN is read once, it frees the saved SYN headers.

The data returned in TCP_SAVED_SYN are network (IPv4/IPv6) and TCP
headers.

Original patch was written by Tom Herbert, I changed it to not hold
a full skb (and associated dst and conntracking reference).

We have used such patch for about 3 years at Google.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Tested-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: fix possible panic in reqsk_queue_unlink()

[ 3897.923145] BUG: unable to handle kernel NULL pointer dereference at
0000000000000080
[ 3897.931025] IP: [<ffffffffa9f27686>] reqsk_timer_handler+0x1a6/0x243

There is a race when reqsk_timer_handler() and tcp_check_req() call
inet_csk_reqsk_queue_unlink() on the same req at the same time.

Before commit fa76ce7328b2 ("inet: get rid of central tcp/dccp listener
timer"), listener spinlock was held and race could not happen.

To solve this bug, we change reqsk_queue_unlink() to not assume req
must be found, and we return a status, to conditionally release a
refcount on the request sock.

This also means tcp_check_req() in non fastopen case might or not
consume req refcount, so tcp_v6_hnd_req() & tcp_v4_hnd_req() have
to properly handle this.

(Same remark for dccp_check_req() and its callers)

inet_csk_reqsk_queue_drop() is now too big to be inlined, as it is
called 4 times in tcp and 3 times in dccp.

Fixes: fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: convert syn_wait_lock to a spinlock

This is a low hanging fruit, as we'll get rid of syn_wait_lock eventually.

We hold syn_wait_lock for such small sections, that it makes no sense to use
a read/write lock. A spin lock is simply faster.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: remove sk_listener parameter from syn_ack_timeout()

It is not needed, and req->sk_listener points to the listener anyway.
request_sock argument can be const.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: get rid of central tcp/dccp listener timer

One of the major issue for TCP is the SYNACK rtx handling,
done by inet_csk_reqsk_queue_prune(), fired by the keepalive
timer of a TCP_LISTEN socket.

This function runs for awful long times, with socket lock held,
meaning that other cpus needing this lock have to spin for hundred of ms.

SYNACK are sent in huge bursts, likely to cause severe drops anyway.

This model was OK 15 years ago when memory was very tight.

We now can afford to have a timer per request sock.

Timer invocations no longer need to lock the listener,
and can be run from all cpus in parallel.

With following patch increasing somaxconn width to 32 bits,
I tested a listener with more than 4 million active request sockets,
and a steady SYNFLOOD of ~200,000 SYN per second.
Host was sending ~830,000 SYNACK per second.

This is ~100 times more what we could achieve before this patch.

Later, we will get rid of the listener hash and use ehash instead.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: drop prev pointer handling in request sock

When request sock are put in ehash table, the whole notion
of having a previous request to update dl_next is pointless.

Also, following patch will get rid of big purge timer,
so we want to delete a request sock without holding listener lock.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: request sock should init IPv6/IPv4 addresses

In order to be able to use sk_ehashfn() for request socks,
we need to initialize their IPv6/IPv4 addresses.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: fix request sock refcounting

While testing last patch series, I found req sock refcounting was wrong.

We must set skc_refcnt to 1 for all request socks added in hashes,
but also on request sockets created by FastOpen or syncookies.

It is tricky because we need to defer this initialization so that
future RCU lookups do not try to take a refcount on a not yet
fully initialized request socket.

Also get rid of ireq_refcnt alias.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 13854e5a6046 ("inet: add proper refcounting to request sock")
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: add rsk_listener field to struct request_sock

Once we'll be able to lookup request sockets in ehash table,
we'll need to get access to listener which created this request.

This avoid doing a lookup to find the listener, which benefits
for a more solid SO_REUSEPORT, and is needed once we no
longer queue request sock into a listener private queue.

Note that 'struct tcp_request_sock'->listener could be reduced
to a single bit, as TFO listener should match req->rsk_listener.
TFO will no longer need to hold a reference on the listener.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: add proper refcounting to request sock

reqsk_put() is the generic function that should be used
to release a refcount (and automatically call reqsk_free())

reqsk_free() might be called if refcount is known to be 0
or undefined.

refcnt is set to one in inet_csk_reqsk_queue_add()

As request socks are not yet in global ehash table,
I added temporary debugging checks in reqsk_put() and reqsk_free()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: prepare sock_edemux() & sock_gen_put() for new SYN_RECV state

sock_edemux() & sock_gen_put() should be ready to cope with request socks.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: add rsk_refcnt/ireq_refcnt to request socks

When request socks will be in ehash, they'll need to be refcounted.

This patch adds rsk_refcnt/ireq_refcnt macros, and adds
reqsk_put() function, but nothing yet use them.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

inet: includes a sock_common in request_sock

TCP listener refactoring, part 5 :

We want to be able to insert request sockets (SYN_RECV) into main
ehash table instead of the per listener hash table to allow RCU
lookups and remove listener lock contention.

This patch includes the needed struct sock_common in front
of struct request_sock

This means there is no more inet6_request_sock IPv6 specific
structure.

Following inet_request_sock fields were renamed as they became
macros to reference fields from struct sock_common.
Prefix ir_ was chosen to avoid name collisions.

loc_port -> ir_loc_port
loc_addr -> ir_loc_addr
rmt_addr -> ir_rmt_addr
rmt_port -> ir_rmt_port
iif -> ir_iif

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

request_sock.h: Remove extern from function prototypes

There are a mix of function prototypes with and without extern
in the kernel sources. Standardize on not using extern for
function prototypes.

Function prototypes don't need to be written with extern.
extern is assumed by the compiler. Its use is as unnecessary as
using auto to declare automatic/local variables in a block.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: remove a stale comment for dl_next

dl_next member in struct request_sock doesn't need to be first.

We expect to insert a "struct common_sock" or a subset of it,
so this claim had to be verified.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: Remove TCPCT

TCPCT uses option-number 253, reserved for experimental use and should
not be used in production environments.
Further, TCPCT does not fully implement RFC 6013.

As a nice side-effect, removing TCPCT increases TCP's performance for
very short flows:

Doing an apache-benchmark with -c 100 -n 100000, sending HTTP-requests
for files of 1KB size.

before this patch:
average (among 7 runs) of 20845.5 Requests/Second
after:
average (among 7 runs) of 21403.6 Requests/Second

Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: better retrans tracking for defer-accept

For passive TCP connections using TCP_DEFER_ACCEPT facility,
we incorrectly increment req->retrans each time timeout triggers
while no SYNACK is sent.

SYNACK are not sent for TCP_DEFER_ACCEPT that were established (for
which we received the ACK from client). Only the last SYNACK is sent
so that we can receive again an ACK from client, to move the req into
accept queue. We plan to change this later to avoid the useless
retransmit (and potential problem as this SYNACK could be lost)

TCP_INFO later gives wrong information to user, claiming imaginary
retransmits.

Decouple req->retrans field into two independent fields :

num_retrans : number of retransmit
num_timeout : number of timeouts

num_timeout is the counter that is incremented at each timeout,
regardless of actual SYNACK being sent or not, and used to
compute the exponential timeout.

Introduce inet_rtx_syn_ack() helper to increment num_retrans
only if ->rtx_syn_ack() succeeded.

Use inet_rtx_syn_ack() from tcp_check_req() to increment num_retrans
when we re-send a SYNACK in answer to a (retransmitted) SYN.
Prior to this patch, we were not counting these retransmits.

Change tcp_v[46]_rtx_synack() to increment TCP_MIB_RETRANSSEGS
only if a synack packet was successfully queued.

Reported-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Julian Anastasov <ja@ssi.bg>
Cc: Vijay Subramanian <subramanian.vijay@gmail.com>
Cc: Elliott Hughes <enh@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: TCP Fast Open Server - support TFO listeners

This patch builds on top of the previous patch to add the support
for TFO listeners. This includes -

1. allocating, properly initializing, and managing the per listener
fastopen_queue structure when TFO is enabled

2. changes to the inet_csk_accept code to support TFO. E.g., the
request_sock can no longer be freed upon accept(), not until 3WHS
finishes

3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg()
if it's a TFO socket

4. properly closing a TFO listener, and a TFO socket before 3WHS
finishes

5. supporting TCP_FASTOPEN socket option

6. modifying tcp_check_req() to use to check a TFO socket as well
as request_sock

7. supporting TCP's TFO cookie option

8. adding a new SYN-ACK retransmit handler to use the timer directly
off the TFO socket rather than the listener socket. Note that TFO
server side will not retransmit anything other than SYN-ACK until
the 3WHS is completed.

The patch also contains an important function
"reqsk_fastopen_remove()" to manage the somewhat complex relation
between a listener, its request_sock, and the corresponding child
socket. See the comment above the function for the detail.

Signed-off-by: H.K. Jerry Chu <hkchu@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: TCP Fast Open Server - header & support functions

This patch adds all the necessary data structure and support
functions to implement TFO server side. It also documents a number
of flags for the sysctl_tcp_fastopen knob, and adds a few Linux
extension MIBs.

In addition, it includes the following:

1. a new TCP_FASTOPEN socket option an application must call to
supply a max backlog allowed in order to enable TFO on its listener.

2. A number of key data structures:
"fastopen_rsk" in tcp_sock - for a big socket to access its
request_sock for retransmission and ack processing purpose. It is
non-NULL iff 3WHS not completed.

"fastopenq" in request_sock_queue - points to a per Fast Open
listener data structure "fastopen_queue" to keep track of qlen (# of
outstanding Fast Open requests) and max_qlen, among other things.

"listener" in tcp_request_sock - to point to the original listener
for book-keeping purpose, i.e., to maintain qlen against max_qlen
as part of defense against IP spoofing attack.

3. various data structure and functions, many in tcp_fastopen.c, to
support server side Fast Open cookie operations, including
/proc/sys/net/ipv4/tcp_fastopen_key to allow manual rekeying.

Signed-off-by: H.K. Jerry Chu <hkchu@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: Change possible SYN flooding messages

"Possible SYN flooding on port xxxx " messages can fill logs on servers.

Change logic to log the message only once per listener, and add two new
SNMP counters to track :

TCPReqQFullDoCookies : number of times a SYNCOOKIE was replied to client

TCPReqQFullDrop : number of times a SYN request was dropped because
syncookies were not enabled.

Based on a prior patch from Tom Herbert, and suggestions from David.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: account SYN-ACK timeouts & retransmissions

Currently we don't increment SYN-ACK timeouts & retransmissions
although we do increment the same stats for SYN. We seem to have lost
the SYN-ACK accounting with the introduction of tcp_syn_recv_timer
(commit 2248761e in the netdev-vger-cvs tree).

This patch fixes this issue. In the process we also rename the v4/v6
syn/ack retransmit functions for clarity. We also add a new
request_socket operations (syn_ack_timeout) so we can keep code in
inet_connection_sock.c protocol agnostic.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

TCPCT part 1a: add request_values parameter for sending SYNACK

Add optional function parameters associated with sending SYNACK.
These parameters are not needed after sending SYNACK, and are not
used for retransmission. Avoids extending struct tcp_request_sock,
and avoids allocating kernel memory.

Also affects DCCP as it uses common struct request_sock_ops,
but this parameter is currently reserved for future use.

Signed-off-by: William.Allen.Simpson@gmail.com
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Fix memory leak in the proto_register function

If the slub allocator is used, kmem_cache_create() may merge two or more
kmem_cache's into one but the cache name pointer is not updated and
kmem_cache_name() is no longer guaranteed to return the pointer passed
to the former function. This patch stores the kmalloc'ed pointers in the
corresponding request_sock_ops and timewait_sock_ops structures.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: Fix kernel panic when calling tcp_v(4/6)_md5_do_lookup

If the following packet flow happen, kernel will panic.
MathineA MathineB
SYN
---------------------->
SYN+ACK
<----------------------
ACK(bad seq)
---------------------->
When a bad seq ACK is received, tcp_v4_md5_do_lookup(skb->sk, ip_hdr(skb)->daddr))
is finally called by tcp_v4_reqsk_send_ack(), but the first parameter(skb->sk) is
NULL at that moment, so kernel panic happens.
This patch fixes this bug.

OOPS output is as following:
[ 302.812793] IP: [<c05cfaa6>] tcp_v4_md5_do_lookup+0x12/0x42
[ 302.817075] Oops: 0000 [#1] SMP
[ 302.819815] Modules linked in: ipv6 loop dm_multipath rtc_cmos rtc_core rtc_lib pcspkr pcnet32 mii i2c_piix4 parport_pc i2c_core parport ac button ata_piix libata dm_mod mptspi mptscsih mptbase scsi_transport_spi sd_mod scsi_mod crc_t10dif ext3 jbd mbcache uhci_hcd ohci_hcd ehci_hcd [last unloaded: scsi_wait_scan]
[ 302.849946]
[ 302.851198] Pid: 0, comm: swapper Not tainted (2.6.27-rc1-guijf #5)
[ 302.855184] EIP: 0060:[<c05cfaa6>] EFLAGS: 00010296 CPU: 0
[ 302.858296] EIP is at tcp_v4_md5_do_lookup+0x12/0x42
[ 302.861027] EAX: 0000001e EBX: 00000000 ECX: 00000046 EDX: 00000046
[ 302.864867] ESI: ceb69e00 EDI: 1467a8c0 EBP: cf75f180 ESP: c0792e54
[ 302.868333] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
[ 302.871287] Process swapper (pid: 0, ti=c0792000 task=c0712340 task.ti=c0746000)
[ 302.875592] Stack: c06f413a 00000000 cf75f180 ceb69e00 00000000 c05d0d86 000016d0 ceac5400
[ 302.883275] c05d28f8 000016d0 ceb69e00 ceb69e20 681bf6e3 00001000 00000000 0a67a8c0
[ 302.890971] ceac5400 c04250a3 c06f413a c0792eb0 c0792edc cf59a620 cf59a620 cf59a634
[ 302.900140] Call Trace:
[ 302.902392] [<c05d0d86>] tcp_v4_reqsk_send_ack+0x17/0x35
[ 302.907060] [<c05d28f8>] tcp_check_req+0x156/0x372
[ 302.910082] [<c04250a3>] printk+0x14/0x18
[ 302.912868] [<c05d0aa1>] tcp_v4_do_rcv+0x1d3/0x2bf
[ 302.917423] [<c05d26be>] tcp_v4_rcv+0x563/0x5b9
[ 302.920453] [<c05bb20f>] ip_local_deliver_finish+0xe8/0x183
[ 302.923865] [<c05bb10a>] ip_rcv_finish+0x286/0x2a3
[ 302.928569] [<c059e438>] dev_alloc_skb+0x11/0x25
[ 302.931563] [<c05a211f>] netif_receive_skb+0x2d6/0x33a
[ 302.934914] [<d0917941>] pcnet32_poll+0x333/0x680 [pcnet32]
[ 302.938735] [<c05a3b48>] net_rx_action+0x5c/0xfe
[ 302.941792] [<c042856b>] __do_softirq+0x5d/0xc1
[ 302.944788] [<c042850e>] __do_softirq+0x0/0xc1
[ 302.948999] [<c040564b>] do_softirq+0x55/0x88
[ 302.951870] [<c04501b1>] handle_fasteoi_irq+0x0/0xa4
[ 302.954986] [<c04284da>] irq_exit+0x35/0x69
[ 302.959081] [<c0405717>] do_IRQ+0x99/0xae
[ 302.961896] [<c040422b>] common_interrupt+0x23/0x28
[ 302.966279] [<c040819d>] default_idle+0x2a/0x3d
[ 302.969212] [<c0402552>] cpu_idle+0xb2/0xd2
[ 302.972169] =======================
[ 302.974274] Code: fc ff 84 d2 0f 84 df fd ff ff e9 34 fe ff ff 83 c4 0c 5b 5e 5f 5d c3 90 90 57 89 d7 56 53 89 c3 50 68 3a 41 6f c0 e8 e9 55 e5 ff <8b> 93 9c 04 00 00 58 85 d2 59 74 1e 8b 72 10 31 db 31 c9 85 f6
[ 303.011610] EIP: [<c05cfaa6>] tcp_v4_md5_do_lookup+0x12/0x42 SS:ESP 0068:c0792e54
[ 303.018360] Kernel panic - not syncing: Fatal exception in interrupt

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: convert BUG_TRAP to generic WARN_ON

Removes legacy reinvent-the-wheel type thing. The generic
machinery integrates much better to automated debugging aids
such as kerneloops.org (and others), and is unambiguous due to
better naming. Non-intuively BUG_TRAP() is actually equal to
WARN_ON() rather than BUG_ON() though some might actually be
promoted to BUG_ON() but I left that to future.

I could make at least one BUILD_BUG_ON conversion.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: Revert 'process defer accept as established' changes.

This reverts two changesets, ec3c0982a2dd1e671bad8e9d26c28dcba0039d87
("[TCP]: TCP_DEFER_ACCEPT updates - process as established") and
the follow-on bug fix 9ae27e0adbf471c7a6b80102e38e1d5a346b3b38
("tcp: Fix slab corruption with ipv6 and tcp6fuzz").

This change causes several problems, first reported by Ingo Molnar
as a distcc-over-loopback regression where connections were getting
stuck.

Ilpo Järvinen first spotted the locking problems. The new function
added by this code, tcp_defer_accept_check(), only has the
child socket locked, yet it is modifying state of the parent
listening socket.

Fixing that is non-trivial at best, because we can't simply just grab
the parent listening socket lock at this point, because it would
create an ABBA deadlock. The normal ordering is parent listening
socket --> child socket, but this code path would require the
reverse lock ordering.

Next is a problem noticed by Vitaliy Gusev, he noted:

----------------------------------------
>--- a/net/ipv4/tcp_timer.c
>+++ b/net/ipv4/tcp_timer.c
>@@ -481,6 +481,11 @@ static void tcp_keepalive_timer (unsigned long data)
> goto death;
> }
>
>+ if (tp->defer_tcp_accept.request && sk->sk_state == TCP_ESTABLISHED) {
>+ tcp_send_active_reset(sk, GFP_ATOMIC);
>+ goto death;

Here socket sk is not attached to listening socket's request queue. tcp_done()
will not call inet_csk_destroy_sock() (and tcp_v4_destroy_sock() which should
release this sk) as socket is not DEAD. Therefore socket sk will be lost for
freeing.
----------------------------------------

Finally, Alexey Kuznetsov argues that there might not even be any
real value or advantage to these new semantics even if we fix all
of the bugs:

----------------------------------------
Hiding from accept() sockets with only out-of-order data only
is the only thing which is impossible with old approach. Is this really
so valuable? My opinion: no, this is nothing but a new loophole
to consume memory without control.
----------------------------------------

So revert this thing for now.

Signed-off-by: David S. Miller <davem@davemloft.net>

[Syncookies]: Add support for TCP options via timestamps.

Allow the use of SACK and window scaling when syncookies are used
and the client supports tcp timestamps. Options are encoded into
the timestamp sent in the syn-ack and restored from the timestamp
echo when the ack is received.

Based on earlier work by Glenn Griffin.
This patch avoids increasing the size of structs by encoding TCP
options into the least significant bits of the timestamp and
by not using any 'timestamp offset'.

The downside is that the timestamp sent in the packet after the synack
will increase by several seconds.

changes since v1:
don't duplicate timestamp echo decoding function, put it into ipv4/syncookie.c
and have ipv6/syncookies.c use it.
Feedback from Glenn Griffin: fix line indented with spaces, kill redundant if ()

Reviewed-by: Hagen Paul Pfeifer <hagen@jauu.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

[TCP]: TCP_DEFER_ACCEPT updates - process as established

Change TCP_DEFER_ACCEPT implementation so that it transitions a
connection to ESTABLISHED after handshake is complete instead of
leaving it in SYN-RECV until some data arrvies. Place connection in
accept queue when first data packet arrives from slow path.

Benefits:
- established connection is now reset if it never makes it
to the accept queue

- diagnostic state of established matches with the packet traces
showing completed handshake

- TCP_DEFER_ACCEPT timeouts are expressed in seconds and can now be
enforced with reasonable accuracy instead of rounding up to next
exponential back-off of syn-ack retry.

Signed-off-by: Patrick McManus <mcmanus@ducksong.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[INET]: Remove struct dst_entry *dst from request_sock_ops.rtx_syn_ack.

It looks like dst parameter is used in this API due to historical
reasons. Actually, it is really used in the direct call to
tcp_v4_send_synack only. So, create a wrapper for tcp_v4_send_synack
and remove dst from rtx_syn_ack.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[INET]: Fix potential kfree on vmalloc-ed area of request_sock_queue

The request_sock_queue's listen_opt is either vmalloc-ed or
kmalloc-ed depending on the number of table entries. Thus it
is expected to be handled properly on free, which is done in
the reqsk_queue_destroy().

However the error path in inet_csk_listen_start() calls
the lite version of reqsk_queue_destroy, called
__reqsk_queue_destroy, which calls the kfree unconditionally.

Fix this and move the __reqsk_queue_destroy into a .c file as
it looks too big to be inline.

As David also noticed, this is an error recovery path only,
so no locking is required and the lopt is known to be not NULL.

reqsk_queue_yank_listen_sk is also now only used in
net/core/request_sock.c so we should move it there too.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[PATCH] slab: remove kmem_cache_t

Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

#!/bin/sh
#
# Replace one string by another in all the kernel sources.
#

set -e

for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
quilt add $file
sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
mv /tmp/$$ $file
quilt refresh
done

The script was run like this

sh replace kmem_cache_t "struct kmem_cache"

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] slab: remove SLAB_ATOMIC

SLAB_ATOMIC is an alias of GFP_ATOMIC

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[TCP]: MD5 Signature Option (RFC2385) support.

Based on implementation by Rick Payne.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: Size listen hash tables using backlog hint

We currently allocate a fixed size (TCP_SYNQ_HSIZE=512) slots hash table for
each LISTEN socket, regardless of various parameters (listen backlog for
example)

On x86_64, this means order-1 allocations (might fail), even for 'small'
sockets, expecting few connections. On the contrary, a huge server wanting a
backlog of 50000 is slowed down a bit because of this fixed limit.

This patch makes the sizing of listen hash table a dynamic parameter,
depending of :
- net.core.somaxconn tunable (default is 128)
- net.ipv4.tcp_max_syn_backlog tunable (default : 256, 1024 or 128)
- backlog value given by user application (2nd parameter of listen())

For large allocations (bigger than PAGE_SIZE), we use vmalloc() instead of
kmalloc().

We still limit memory allocation with the two existing tunables (somaxconn &
tcp_max_syn_backlog). So for standard setups, this patch actually reduce RAM
usage.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

SELinux: Return correct context for SO_PEERSEC

Fix SO_PEERSEC for tcp sockets to return the security context of
the peer (as represented by the SA from the peer) as opposed to the
SA used by the local/source socket.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: James Morris <jmorris@namei.org>

[MLSXFRM]: Auto-labeling of child sockets

This automatically labels the TCP, Unix stream, and dccp child sockets
as well as openreqs to be at the same MLS level as the peer. This will
result in the selection of appropriately labeled IPSec Security
Associations.

This also uses the sock's sid (as opposed to the isec sid) in SELinux
enforcement of secmark in rcv_skb and postroute_last hooks.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: drop duplicate assignment in request_sock

Just noticed that request_sock.[ch] contain a useless assignment of
rskq_accept_head to itself. I assume this is a typo and the 2nd one
was supposed to be _tail. However, setting _tail to NULL is not
needed, so the patch below just drops the 2nd assignment.

Signed-off-By: Norbert Kiesel <nkiesel@tbdnetworks.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

[IPV6]: Generalise tcp_v6_search_req & tcp_v6_synq_add

More work is needed tho to introduce inet6_request_sock from
tcp6_request_sock, in the same layout considerations as ipv6_pinfo in
inet_sock, next changeset will do that.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

[ICSK]: Move generalised functions from tcp to inet_connection_sock

This also improves reqsk_queue_prune and renames it to
inet_csk_reqsk_queue_prune, as it deals with both inet_connection_sock
and inet_request_sock objects, not just with request_sock ones thus
belonging to inet_request_sock.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[ICSK]: Introduce reqsk_queue_prune from code in tcp_synack_timer

With this we're very close to getting all of the current TCP
refactorings in my dccp-2.6 tree merged, next changeset will export
some functions needed by the current DCCP code and then dccp-2.6.git
will be born!

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: Introduce inet_connection_sock

This creates struct inet_connection_sock, moving members out of struct
tcp_sock that are shareable with other INET connection oriented
protocols, such as DCCP, that in my private tree already uses most of
these members.

The functions that operate on these members were renamed, using a
inet_csk_ prefix while not being moved yet to a new file, so as to
ease the review of these changes.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[REQSK]: Move the syn_table destroy from tcp_listen_stop to reqsk_queue_destroy

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET] rename struct tcp_listen_opt to struct listen_sock

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET] Generalise tcp_listen_opt

This chunks out the accept_queue and tcp_listen_opt code and moves
them to net/core/request_sock.c and include/net/request_sock.h, to
make it useful for other transport protocols, DCCP being the first one
to use it.

Next patches will rename tcp_listen_opt to accept_sock and remove the
inline tcp functions that just call a reqsk_queue_ function.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET] Rename open_request to request_sock

Ok, this one just renames some stuff to have a better namespace and to
dissassociate it from TCP:

struct open_request -> struct request_sock
tcp_openreq_alloc -> reqsk_alloc
tcp_openreq_free -> reqsk_free
tcp_openreq_fastfree -> __reqsk_free

With this most of the infrastructure closely resembles a struct
sock methods subset.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NET] Generalise TCP's struct open_request minisock infrastructure

Kept this first changeset minimal, without changing existing names to
ease peer review.

Basicaly tcp_openreq_alloc now receives the or_calltable, that in turn
has two new members:

->slab, that replaces tcp_openreq_cachep
->obj_size, to inform the size of the openreq descendant for
a specific protocol

The protocol specific fields in struct open_request were moved to a
class hierarchy, with the things that are common to all connection
oriented PF_INET protocols in struct inet_request_sock, the TCP ones
in tcp_request_sock, that is an inet_request_sock, that is an
open_request.

I.e. this uses the same approach used for the struct sock class
hierarchy, with sk_prot indicating if the protocol wants to use the
open_request infrastructure by filling in sk_prot->rsk_prot with an
or_calltable.

Results? Performance is improved and TCP v4 now uses only 64 bytes per
open request minisock, down from 96 without this patch :-)

Next changeset will rename some of the structs, fields and functions
mentioned above, struct or_calltable is way unclear, better name it
struct request_sock_ops, s/struct open_request/struct request_sock/g,
etc.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>