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2019-10-09net: add {READ|WRITE}_ONCE() annotations on ->rskq_accept_headEric Dumazet1-2/+2
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>
2019-06-19inet: clear num_timeout reqsk_alloc()Eric Dumazet1-0/+3
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>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner1-5/+1
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>
2019-03-19tcp: free request sock directly upon TFO or syncookies errorGuillaume Nault1-3/+7
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>
2019-03-09net: keep refcount warning in reqsk_free()Guillaume Nault1-1/+0
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>
2017-10-20tcp: socket option to set TCP fast open keyYuchung Cheng1-0/+2
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>
2017-07-01net: convert sock.sk_refcnt from atomic_t to refcount_tReshetova, Elena1-4/+5
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>
2017-05-23net: make struct request_sock_ops::obj_size unsignedAlexey Dobriyan1-1/+1
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>
2016-12-29ipv4: Namespaceify tcp_max_syn_backlog knobHaishuang Yan1-3/+1
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>
2016-04-04inet: reqsk_alloc() needs to take care of dead listenersEric Dumazet1-16/+15
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>
2015-12-22net: add inet_sk_transparent() helperFlorian Westphal1-1/+1
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>
2015-10-16tcp/dccp: fix race at listener dismantle phaseEric Dumazet1-19/+0
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>
2015-10-12net: shrink struct sock and request_sock by 8 bytesEric Dumazet1-3/+2
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>
2015-10-12net: align sk_refcnt on 128 bytes boundaryEric Dumazet1-1/+1
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>
2015-10-05tcp: avoid two atomic ops for syncookiesEric Dumazet1-3/+8
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>
2015-10-05net: use sk_fullsock() in __netdev_pick_tx()Eric Dumazet1-0/+1
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>
2015-10-03tcp/dccp: add SLAB_DESTROY_BY_RCU flag for request socketsEric Dumazet1-1/+3
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>
2015-10-03tcp: remove max_qlen_logEric Dumazet1-8/+2
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>
2015-10-03tcp/dccp: remove struct listen_sockEric Dumazet1-22/+4
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>
2015-10-03tcp/dccp: shrink struct listen_sockEric Dumazet1-3/+0
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>
2015-10-03tcp/dccp: install syn_recv requests into ehash tableEric Dumazet1-4/+0
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>
2015-10-03tcp/dccp: init sk_prot and call sk_node_init() in reqsk_alloc()Eric Dumazet1-10/+12
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>
2015-10-03tcp: move synflood_warned into struct request_sock_queueEric Dumazet1-1/+1
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>
2015-10-03tcp: move qlen/young out of struct listen_sockEric Dumazet1-30/+10
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>
2015-10-03tcp: add a spinlock to protect struct request_sock_queueEric Dumazet1-19/+18
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>
2015-09-29tcp: prepare fastopen code for upcoming listener changesEric Dumazet1-5/+2
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>
2015-09-29tcp: constify tcp_syn_flood_action() socket argumentEric Dumazet1-3/+2
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>
2015-09-29tcp/dccp: constify send_synack and send_reset socket argumentEric Dumazet1-2/+2
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>
2015-09-25inet: constify inet_rtx_syn_ack() sock argumentEric Dumazet1-1/+1
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>
2015-09-25tcp/dccp: constify rtx_synack() and friendsEric Dumazet1-1/+1
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>
2015-05-05tcp: provide SYN headers for passive connectionsEric Dumazet1-1/+3
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>
2015-04-24inet: fix possible panic in reqsk_queue_unlink()Eric Dumazet1-18/+0
[ 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>
2015-03-23net: convert syn_wait_lock to a spinlockEric Dumazet1-8/+3
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>
2015-03-23inet: remove sk_listener parameter from syn_ack_timeout()Eric Dumazet1-2/+1
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>
2015-03-20inet: get rid of central tcp/dccp listener timerEric Dumazet1-46/+41
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>
2015-03-20inet: drop prev pointer handling in request sockEric Dumazet1-4/+11
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>
2015-03-18inet: request sock should init IPv6/IPv4 addressesEric Dumazet1-0/+5
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>
2015-03-17inet: fix request sock refcountingEric Dumazet1-0/+11
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>
2015-03-17inet: add rsk_listener field to struct request_sockEric Dumazet1-3/+9
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>
2015-03-16inet: add proper refcounting to request sockEric Dumazet1-6/+7
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>
2015-03-12inet: prepare sock_edemux() & sock_gen_put() for new SYN_RECV stateEric Dumazet1-0/+5
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>
2015-03-12inet: add rsk_refcnt/ireq_refcnt to request socksEric Dumazet1-0/+8
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>
2013-10-10inet: includes a sock_common in request_sockEric Dumazet1-0/+1
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>
2013-09-23request_sock.h: Remove extern from function prototypesJoe Perches1-7/+7
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>
2013-04-22net: remove a stale comment for dl_nextEric Dumazet1-1/+1
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>
2013-03-17tcp: Remove TCPCTChristoph Paasch1-7/+1
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>
2012-11-03tcp: better retrans tracking for defer-acceptEric Dumazet1-4/+8
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>
2012-08-31tcp: TCP Fast Open Server - support TFO listenersJerry Chu1-13/+0
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>
2012-08-31tcp: TCP Fast Open Server - header & support functionsJerry Chu1-0/+36
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>
2011-09-15tcp: Change possible SYN flooding messagesEric Dumazet1-1/+2
"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>
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