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path: root/net/ipv4/tcp_ipv4.c
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2022-12-02tcp: use 2-arg optimal variant of kfree_rcu()Eric Dumazet
kfree_rcu(1-arg) should be avoided as much as possible, since this is only possible from sleepable contexts, and incurr extra rcu barriers. I wish the 1-arg variant of kfree_rcu() would get a distinct name, like kfree_rcu_slow() to avoid it being abused. Fixes: 459837b522f7 ("net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destruction") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com> Reviewed-by: Dmitry Safonov <dima@arista.com> Link: https://lore.kernel.org/r/20221202052847.2623997-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-01net/tcp: Do cleanup on tcp_md5_key_copy() failureDmitry Safonov
If the kernel was short on (atomic) memory and failed to allocate it - don't proceed to creation of request socket. Otherwise the socket would be unsigned and userspace likely doesn't expect that the TCP is not MD5-signed anymore. Signed-off-by: Dmitry Safonov <dima@arista.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-01net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destructionDmitry Safonov
To do that, separate two scenarios: - where it's the first MD5 key on the system, which means that enabling of the static key may need to sleep; - copying of an existing key from a listening socket to the request socket upon receiving a signed TCP segment, where static key was already enabled (when the key was added to the listening socket). Now the life-time of the static branch for TCP-MD5 is until: - last tcp_md5sig_info is destroyed - last socket in time-wait state with MD5 key is closed. Which means that after all sockets with TCP-MD5 keys are gone, the system gets back the performance of disabled md5-key static branch. While at here, provide static_key_fast_inc() helper that does ref counter increment in atomic fashion (without grabbing cpus_read_lock() on CONFIG_JUMP_LABEL=y). This is needed to add a new user for a static_key when the caller controls the lifetime of another user. Signed-off-by: Dmitry Safonov <dima@arista.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-12-01net/tcp: Separate tcp_md5sig_info allocation into tcp_md5sig_info_add()Dmitry Safonov
Add a helper to allocate tcp_md5sig_info, that will help later to do/allocate things when info allocated, once per socket. Signed-off-by: Dmitry Safonov <dima@arista.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-29Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
tools/lib/bpf/ringbuf.c 927cbb478adf ("libbpf: Handle size overflow for ringbuf mmap") b486d19a0ab0 ("libbpf: checkpatch: Fixed code alignments in ringbuf.c") https://lore.kernel.org/all/20221121122707.44d1446a@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-22dccp/tcp: Fixup bhash2 bucket when connect() fails.Kuniyuki Iwashima
If a socket bound to a wildcard address fails to connect(), we only reset saddr and keep the port. Then, we have to fix up the bhash2 bucket; otherwise, the bucket has an inconsistent address in the list. Also, listen() for such a socket will fire the WARN_ON() in inet_csk_get_port(). [0] Note that when a system runs out of memory, we give up fixing the bucket and unlink sk from bhash and bhash2 by inet_put_port(). [0]: WARNING: CPU: 0 PID: 207 at net/ipv4/inet_connection_sock.c:548 inet_csk_get_port (net/ipv4/inet_connection_sock.c:548 (discriminator 1)) Modules linked in: CPU: 0 PID: 207 Comm: bhash2_prev_rep Not tainted 6.1.0-rc3-00799-gc8421681c845 #63 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014 RIP: 0010:inet_csk_get_port (net/ipv4/inet_connection_sock.c:548 (discriminator 1)) Code: 74 a7 eb 93 48 8b 54 24 18 0f b7 cb 4c 89 e6 4c 89 ff e8 48 b2 ff ff 49 8b 87 18 04 00 00 e9 32 ff ff ff 0f 0b e9 34 ff ff ff <0f> 0b e9 42 ff ff ff 41 8b 7f 50 41 8b 4f 54 89 fe 81 f6 00 00 ff RSP: 0018:ffffc900003d7e50 EFLAGS: 00010202 RAX: ffff8881047fb500 RBX: 0000000000004e20 RCX: 0000000000000000 RDX: 000000000000000a RSI: 00000000fffffe00 RDI: 00000000ffffffff RBP: ffffffff8324dc00 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000004e20 R15: ffff8881054e1280 FS: 00007f8ac04dc740(0000) GS:ffff88842fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001540 CR3: 00000001055fa003 CR4: 0000000000770ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> inet_csk_listen_start (net/ipv4/inet_connection_sock.c:1205) inet_listen (net/ipv4/af_inet.c:228) __sys_listen (net/socket.c:1810) __x64_sys_listen (net/socket.c:1819 net/socket.c:1817 net/socket.c:1817) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) RIP: 0033:0x7f8ac051de5d Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 93 af 1b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc1c177248 EFLAGS: 00000206 ORIG_RAX: 0000000000000032 RAX: ffffffffffffffda RBX: 0000000020001550 RCX: 00007f8ac051de5d RDX: ffffffffffffff80 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007ffc1c177270 R08: 0000000000000018 R09: 0000000000000007 R10: 0000000020001540 R11: 0000000000000206 R12: 00007ffc1c177388 R13: 0000000000401169 R14: 0000000000403e18 R15: 00007f8ac0723000 </TASK> Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address") Reported-by: syzbot <syzkaller@googlegroups.com> Reported-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-22dccp/tcp: Update saddr under bhash's lock.Kuniyuki Iwashima
When we call connect() for a socket bound to a wildcard address, we update saddr locklessly. However, it could result in a data race; another thread iterating over bhash might see a corrupted address. Let's update saddr under the bhash bucket's lock. Fixes: 3df80d9320bc ("[DCCP]: Introduce DCCPv6") Fixes: 7c657876b63c ("[DCCP]: Initial implementation") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-22dccp/tcp: Reset saddr on failure after inet6?_hash_connect().Kuniyuki Iwashima
When connect() is called on a socket bound to the wildcard address, we change the socket's saddr to a local address. If the socket fails to connect() to the destination, we have to reset the saddr. However, when an error occurs after inet_hash6?_connect() in (dccp|tcp)_v[46]_conect(), we forget to reset saddr and leave the socket bound to the address. From the user's point of view, whether saddr is reset or not varies with errno. Let's fix this inconsistent behaviour. Note that after this patch, the repro [0] will trigger the WARN_ON() in inet_csk_get_port() again, but this patch is not buggy and rather fixes a bug papering over the bhash2's bug for which we need another fix. For the record, the repro causes -EADDRNOTAVAIL in inet_hash6_connect() by this sequence: s1 = socket() s1.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1) s1.bind(('127.0.0.1', 10000)) s1.sendto(b'hello', MSG_FASTOPEN, (('127.0.0.1', 10000))) # or s1.connect(('127.0.0.1', 10000)) s2 = socket() s2.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1) s2.bind(('0.0.0.0', 10000)) s2.connect(('127.0.0.1', 10000)) # -EADDRNOTAVAIL s2.listen(32) # WARN_ON(inet_csk(sk)->icsk_bind2_hash != tb2); [0]: https://syzkaller.appspot.com/bug?extid=015d756bbd1f8b5c8f09 Fixes: 3df80d9320bc ("[DCCP]: Introduce DCCPv6") Fixes: 7c657876b63c ("[DCCP]: Initial implementation") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-11-14ipasdv4/tcp_ipv4: remove redundant assignmentxu xin
The value of 'st->state' has been verified as "TCP_SEQ_STATE_LISTENING", it's unnecessary to assign TCP_SEQ_STATE_LISTENING to it, so we can remove it. Signed-off-by: xu xin <xu.xin16@zte.com.cn> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-28tcp: add PLB functionality for TCPMubashir Adnan Qureshi
Congestion control algorithms track PLB state and cause the connection to trigger a path change when either of the 2 conditions is satisfied: - No packets are in flight and (# consecutive congested rounds >= sysctl_tcp_plb_idle_rehash_rounds) - (# consecutive congested rounds >= sysctl_tcp_plb_rehash_rounds) A round (RTT) is marked as congested when congestion signal (ECN ce_ratio) over an RTT is greater than sysctl_tcp_plb_cong_thresh. In the event of RTO, PLB (via tcp_write_timeout()) triggers a path change and disables congestion-triggered path changes for random time between (sysctl_tcp_plb_suspend_rto_sec, 2*sysctl_tcp_plb_suspend_rto_sec) to avoid hopping onto the "connectivity blackhole". RTO-triggered path changes can still happen during this cool-off period. Signed-off-by: Mubashir Adnan Qureshi <mubashirq@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-28tcp: add sysctls for TCP PLB parametersMubashir Adnan Qureshi
PLB (Protective Load Balancing) is a host based mechanism for load balancing across switch links. It leverages congestion signals(e.g. ECN) from transport layer to randomly change the path of the connection experiencing congestion. PLB changes the path of the connection by changing the outgoing IPv6 flow label for IPv6 connections (implemented in Linux by calling sk_rethink_txhash()). Because of this implementation mechanism, PLB can currently only work for IPv6 traffic. For more information, see the SIGCOMM 2022 paper: https://doi.org/10.1145/3544216.3544226 This commit adds new sysctl knobs and sets their default values for TCP PLB. Signed-off-by: Mubashir Adnan Qureshi <mubashirq@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-24tcp: fix a signed-integer-overflow bug in tcp_add_backlog()Lu Wei
The type of sk_rcvbuf and sk_sndbuf in struct sock is int, and in tcp_add_backlog(), the variable limit is caculated by adding sk_rcvbuf, sk_sndbuf and 64 * 1024, it may exceed the max value of int and overflow. This patch reduces the limit budget by halving the sndbuf to solve this issue since ACK packets are much smaller than the payload. Fixes: c9c3321257e1 ("tcp: add tcp_add_backlog()") Signed-off-by: Lu Wei <luwei32@huawei.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-11treewide: use get_random_{u8,u16}() when possible, part 1Jason A. Donenfeld
Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value, simply use the get_random_{u8,u16}() functions, which are faster than wasting the additional bytes from a 32-bit value. This was done mechanically with this coccinelle script: @@ expression E; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u16; typedef __be16; typedef __le16; typedef u8; @@ ( - (get_random_u32() & 0xffff) + get_random_u16() | - (get_random_u32() & 0xff) + get_random_u8() | - (get_random_u32() % 65536) + get_random_u16() | - (get_random_u32() % 256) + get_random_u8() | - (get_random_u32() >> 16) + get_random_u16() | - (get_random_u32() >> 24) + get_random_u8() | - (u16)get_random_u32() + get_random_u16() | - (u8)get_random_u32() + get_random_u8() | - (__be16)get_random_u32() + (__be16)get_random_u16() | - (__le16)get_random_u32() + (__le16)get_random_u16() | - prandom_u32_max(65536) + get_random_u16() | - prandom_u32_max(256) + get_random_u8() | - E->inet_id = get_random_u32() + E->inet_id = get_random_u16() ) @@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u16; identifier v; @@ - u16 v = get_random_u32(); + u16 v = get_random_u16(); @@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u8; identifier v; @@ - u8 v = get_random_u32(); + u8 v = get_random_u8(); @@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u16; u16 v; @@ - v = get_random_u32(); + v = get_random_u16(); @@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u8; u8 v; @@ - v = get_random_u32(); + v = get_random_u8(); // Find a potential literal @literal_mask@ expression LITERAL; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; position p; @@ ((T)get_random_u32()@p & (LITERAL)) // Examine limits @script:python add_one@ literal << literal_mask.LITERAL; RESULT; @@ value = None if literal.startswith('0x'): value = int(literal, 16) elif literal[0] in '123456789': value = int(literal, 10) if value is None: print("I don't know how to handle %s" % (literal)) cocci.include_match(False) elif value < 256: coccinelle.RESULT = cocci.make_ident("get_random_u8") elif value < 65536: coccinelle.RESULT = cocci.make_ident("get_random_u16") else: print("Skipping large mask of %s" % (literal)) cocci.include_match(False) // Replace the literal mask with the calculated result. @plus_one@ expression literal_mask.LITERAL; position literal_mask.p; identifier add_one.RESULT; identifier FUNC; @@ - (FUNC()@p & (LITERAL)) + (RESULT() & LITERAL) Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Yury Norov <yury.norov@gmail.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-09-20tcp: Introduce optional per-netns ehash.Kuniyuki Iwashima
The more sockets we have in the hash table, the longer we spend looking up the socket. While running a number of small workloads on the same host, they penalise each other and cause performance degradation. The root cause might be a single workload that consumes much more resources than the others. It often happens on a cloud service where different workloads share the same computing resource. On EC2 c5.24xlarge instance (196 GiB memory and 524288 (1Mi / 2) ehash entries), after running iperf3 in different netns, creating 24Mi sockets without data transfer in the root netns causes about 10% performance regression for the iperf3's connection. thash_entries sockets length Gbps 524288 1 1 50.7 24Mi 48 45.1 It is basically related to the length of the list of each hash bucket. For testing purposes to see how performance drops along the length, I set 131072 (1Mi / 8) to thash_entries, and here's the result. thash_entries sockets length Gbps 131072 1 1 50.7 1Mi 8 49.9 2Mi 16 48.9 4Mi 32 47.3 8Mi 64 44.6 16Mi 128 40.6 24Mi 192 36.3 32Mi 256 32.5 40Mi 320 27.0 48Mi 384 25.0 To resolve the socket lookup degradation, we introduce an optional per-netns hash table for TCP, but it's just ehash, and we still share the global bhash, bhash2 and lhash2. With a smaller ehash, we can look up non-listener sockets faster and isolate such noisy neighbours. In addition, we can reduce lock contention. We can control the ehash size by a new sysctl knob. However, depending on workloads, it will require very sensitive tuning, so we disable the feature by default (net.ipv4.tcp_child_ehash_entries == 0). Moreover, we can fall back to using the global ehash in case we fail to allocate enough memory for a new ehash. The maximum size is 16Mi, which is large enough that even if we have 48Mi sockets, the average list length is 3, and regression would be less than 1%. We can check the current ehash size by another read-only sysctl knob, net.ipv4.tcp_ehash_entries. A negative value means the netns shares the global ehash (per-netns ehash is disabled or failed to allocate memory). # dmesg | cut -d ' ' -f 5- | grep "established hash" TCP established hash table entries: 524288 (order: 10, 4194304 bytes, vmalloc hugepage) # sysctl net.ipv4.tcp_ehash_entries net.ipv4.tcp_ehash_entries = 524288 # can be changed by thash_entries # sysctl net.ipv4.tcp_child_ehash_entries net.ipv4.tcp_child_ehash_entries = 0 # disabled by default # ip netns add test1 # ip netns exec test1 sysctl net.ipv4.tcp_ehash_entries net.ipv4.tcp_ehash_entries = -524288 # share the global ehash # sysctl -w net.ipv4.tcp_child_ehash_entries=100 net.ipv4.tcp_child_ehash_entries = 100 # ip netns add test2 # ip netns exec test2 sysctl net.ipv4.tcp_ehash_entries net.ipv4.tcp_ehash_entries = 128 # own a per-netns ehash with 2^n buckets When more than two processes in the same netns create per-netns ehash concurrently with different sizes, we need to guarantee the size in one of the following ways: 1) Share the global ehash and create per-netns ehash First, unshare() with tcp_child_ehash_entries==0. It creates dedicated netns sysctl knobs where we can safely change tcp_child_ehash_entries and clone()/unshare() to create a per-netns ehash. 2) Control write on sysctl by BPF We can use BPF_PROG_TYPE_CGROUP_SYSCTL to allow/deny read/write on sysctl knobs. Note that the global ehash allocated at the boot time is spread over available NUMA nodes, but inet_pernet_hashinfo_alloc() will allocate pages for each per-netns ehash depending on the current process's NUMA policy. By default, the allocation is done in the local node only, so the per-netns hash table could fully reside on a random node. Thus, depending on the NUMA policy the netns is created with and the CPU the current thread is running on, we could see some performance differences for highly optimised networking applications. Note also that the default values of two sysctl knobs depend on the ehash size and should be tuned carefully: tcp_max_tw_buckets : tcp_child_ehash_entries / 2 tcp_max_syn_backlog : max(128, tcp_child_ehash_entries / 128) As a bonus, we can dismantle netns faster. Currently, while destroying netns, we call inet_twsk_purge(), which walks through the global ehash. It can be potentially big because it can have many sockets other than TIME_WAIT in all netns. Splitting ehash changes that situation, where it's only necessary for inet_twsk_purge() to clean up TIME_WAIT sockets in each netns. With regard to this, we do not free the per-netns ehash in inet_twsk_kill() to avoid UAF while iterating the per-netns ehash in inet_twsk_purge(). Instead, we do it in tcp_sk_exit_batch() after calling tcp_twsk_purge() to keep it protocol-family-independent. In the future, we could optimise ehash lookup/iteration further by removing netns comparison for the per-netns ehash. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-20tcp: Save unnecessary inet_twsk_purge() calls.Kuniyuki Iwashima
While destroying netns, we call inet_twsk_purge() in tcp_sk_exit_batch() and tcpv6_net_exit_batch() for AF_INET and AF_INET6. These commands trigger the kernel to walk through the potentially big ehash twice even though the netns has no TIME_WAIT sockets. # ip netns add test # ip netns del test or # unshare -n /bin/true >/dev/null When tw_refcount is 1, we need not call inet_twsk_purge() at least for the net. We can save such unneeded iterations if all netns in net_exit_list have no TIME_WAIT sockets. This change eliminates the tax by the additional unshare() described in the next patch to guarantee the per-netns ehash size. Tested: # mount -t debugfs none /sys/kernel/debug/ # echo cleanup_net > /sys/kernel/debug/tracing/set_ftrace_filter # echo inet_twsk_purge >> /sys/kernel/debug/tracing/set_ftrace_filter # echo function > /sys/kernel/debug/tracing/current_tracer # cat ./add_del_unshare.sh for i in `seq 1 40` do (for j in `seq 1 100` ; do unshare -n /bin/true >/dev/null ; done) & done wait; # ./add_del_unshare.sh Before the patch: # cat /sys/kernel/debug/tracing/trace_pipe kworker/u128:0-8 [031] ...1. 174.162765: cleanup_net <-process_one_work kworker/u128:0-8 [031] ...1. 174.240796: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [032] ...1. 174.244759: inet_twsk_purge <-tcp_sk_exit_batch kworker/u128:0-8 [034] ...1. 174.290861: cleanup_net <-process_one_work kworker/u128:0-8 [039] ...1. 175.245027: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [046] ...1. 175.290541: inet_twsk_purge <-tcp_sk_exit_batch kworker/u128:0-8 [037] ...1. 175.321046: cleanup_net <-process_one_work kworker/u128:0-8 [024] ...1. 175.941633: inet_twsk_purge <-cleanup_net kworker/u128:0-8 [025] ...1. 176.242539: inet_twsk_purge <-tcp_sk_exit_batch After: # cat /sys/kernel/debug/tracing/trace_pipe kworker/u128:0-8 [038] ...1. 428.116174: cleanup_net <-process_one_work kworker/u128:0-8 [038] ...1. 428.262532: cleanup_net <-process_one_work kworker/u128:0-8 [030] ...1. 429.292645: cleanup_net <-process_one_work Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-20tcp: Access &tcp_hashinfo via net.Kuniyuki Iwashima
We will soon introduce an optional per-netns ehash. This means we cannot use tcp_hashinfo directly in most places. Instead, access it via net->ipv4.tcp_death_row.hashinfo. The access will be valid only while initialising tcp_hashinfo itself and creating/destroying each netns. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-20tcp: Set NULL to sk->sk_prot->h.hashinfo.Kuniyuki Iwashima
We will soon introduce an optional per-netns ehash. This means we cannot use the global sk->sk_prot->h.hashinfo to fetch a TCP hashinfo. Instead, set NULL to sk->sk_prot->h.hashinfo for TCP and get a proper hashinfo from net->ipv4.tcp_death_row.hashinfo. Note that we need not use sk->sk_prot->h.hashinfo if DCCP is disabled. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-20tcp: Don't allocate tcp_death_row outside of struct netns_ipv4.Kuniyuki Iwashima
We will soon introduce an optional per-netns ehash and access hash tables via net->ipv4.tcp_death_row->hashinfo instead of &tcp_hashinfo in most places. It could harm the fast path because dereferences of two fields in net and tcp_death_row might incur two extra cache line misses. To save one dereference, let's place tcp_death_row back in netns_ipv4 and fetch hashinfo via net->ipv4.tcp_death_row"."hashinfo. Note tcp_death_row was initially placed in netns_ipv4, and commit fbb8295248e1 ("tcp: allocate tcp_death_row outside of struct netns_ipv4") changed it to a pointer so that we can fire TIME_WAIT timers after freeing net. However, we don't do so after commit 04c494e68a13 ("Revert "tcp/dccp: get rid of inet_twsk_purge()""), so we need not define tcp_death_row as a pointer. Also, we move refcount_dec_and_test(&tw_refcount) from tcp_sk_exit() to tcp_sk_exit_batch() as a debug check. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-20tcp: Clean up some functions.Kuniyuki Iwashima
This patch adds no functional change and cleans up some functions that the following patches touch around so that we make them tidy and easy to review/revert. The changes are - Keep reverse christmas tree order - Remove unnecessary init of port in inet_csk_find_open_port() - Use req_to_sk() once in reqsk_queue_unlink() - Use sock_net(sk) once in tcp_time_wait() and tcp_v[46]_connect() Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
tools/testing/selftests/net/.gitignore sort the net-next version and use it Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-31tcp: make global challenge ack rate limitation per net-ns and default disabledEric Dumazet
Because per host rate limiting has been proven problematic (side channel attacks can be based on it), per host rate limiting of challenge acks ideally should be per netns and turned off by default. This is a long due followup of following commits: 083ae308280d ("tcp: enable per-socket rate limiting of all 'challenge acks'") f2b2c582e824 ("tcp: mitigate ACK loops for connections as tcp_sock") 75ff39ccc1bd ("tcp: make challenge acks less predictable") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jason Baron <jbaron@akamai.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-24net: Add a bhash2 table hashed by port and addressJoanne Koong
The current bind hashtable (bhash) is hashed by port only. In the socket bind path, we have to check for bind conflicts by traversing the specified port's inet_bind_bucket while holding the hashbucket's spinlock (see inet_csk_get_port() and inet_csk_bind_conflict()). In instances where there are tons of sockets hashed to the same port at different addresses, the bind conflict check is time-intensive and can cause softirq cpu lockups, as well as stops new tcp connections since __inet_inherit_port() also contests for the spinlock. This patch adds a second bind table, bhash2, that hashes by port and sk->sk_rcv_saddr (ipv4) and sk->sk_v6_rcv_saddr (ipv6). Searching the bhash2 table leads to significantly faster conflict resolution and less time holding the hashbucket spinlock. Please note a few things: * There can be the case where the a socket's address changes after it has been bound. There are two cases where this happens: 1) The case where there is a bind() call on INADDR_ANY (ipv4) or IPV6_ADDR_ANY (ipv6) and then a connect() call. The kernel will assign the socket an address when it handles the connect() 2) In inet_sk_reselect_saddr(), which is called when rebuilding the sk header and a few pre-conditions are met (eg rerouting fails). In these two cases, we need to update the bhash2 table by removing the entry for the old address, and add a new entry reflecting the updated address. * The bhash2 table must have its own lock, even though concurrent accesses on the same port are protected by the bhash lock. Bhash2 must have its own lock to protect against cases where sockets on different ports hash to different bhash hashbuckets but to the same bhash2 hashbucket. This brings up a few stipulations: 1) When acquiring both the bhash and the bhash2 lock, the bhash2 lock will always be acquired after the bhash lock and released before the bhash lock is released. 2) There are no nested bhash2 hashbucket locks. A bhash2 lock is always acquired+released before another bhash2 lock is acquired+released. * The bhash table cannot be superseded by the bhash2 table because for bind requests on INADDR_ANY (ipv4) or IPV6_ADDR_ANY (ipv6), every socket bound to that port must be checked for a potential conflict. The bhash table is the only source of port->socket associations. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-28Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-25tcp: Fix data-races around sysctl_tcp_reflect_tos.Kuniyuki Iwashima
While reading sysctl_tcp_reflect_tos, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: ac8f1710c12b ("tcp: reflect tos value received in SYN to the socket") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Wei Wang <weiwan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-18tcp: Fix a data-race around sysctl_tcp_tw_reuse.Kuniyuki Iwashima
While reading sysctl_tcp_tw_reuse, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-11net: Find dst with sk's xfrm policy not ctl_sksewookseo
If we set XFRM security policy by calling setsockopt with option IPV6_XFRM_POLICY, the policy will be stored in 'sock_policy' in 'sock' struct. However tcp_v6_send_response doesn't look up dst_entry with the actual socket but looks up with tcp control socket. This may cause a problem that a RST packet is sent without ESP encryption & peer's TCP socket can't receive it. This patch will make the function look up dest_entry with actual socket, if the socket has XFRM policy(sock_policy), so that the TCP response packet via this function can be encrypted, & aligned on the encrypted TCP socket. Tested: We encountered this problem when a TCP socket which is encrypted in ESP transport mode encryption, receives challenge ACK at SYN_SENT state. After receiving challenge ACK, TCP needs to send RST to establish the socket at next SYN try. But the RST was not encrypted & peer TCP socket still remains on ESTABLISHED state. So we verified this with test step as below. [Test step] 1. Making a TCP state mismatch between client(IDLE) & server(ESTABLISHED). 2. Client tries a new connection on the same TCP ports(src & dst). 3. Server will return challenge ACK instead of SYN,ACK. 4. Client will send RST to server to clear the SOCKET. 5. Client will retransmit SYN to server on the same TCP ports. [Expected result] The TCP connection should be established. Cc: Maciej Żenczykowski <maze@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: Sehee Lee <seheele@google.com> Signed-off-by: Sewook Seo <sewookseo@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-06-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
drivers/net/ethernet/microchip/sparx5/sparx5_switchdev.c 9c5de246c1db ("net: sparx5: mdb add/del handle non-sparx5 devices") fbb89d02e33a ("net: sparx5: Allow mdb entries to both CPU and ports") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-24tcp: add a missing nf_reset_ct() in 3WHS handlingEric Dumazet
When the third packet of 3WHS connection establishment contains payload, it is added into socket receive queue without the XFRM check and the drop of connection tracking context. This means that if the data is left unread in the socket receive queue, conntrack module can not be unloaded. As most applications usually reads the incoming data immediately after accept(), bug has been hiding for quite a long time. Commit 68822bdf76f1 ("net: generalize skb freeing deferral to per-cpu lists") exposed this bug because even if the application reads this data, the skb with nfct state could stay in a per-cpu cache for an arbitrary time, if said cpu no longer process RX softirqs. Many thanks to Ilya Maximets for reporting this issue, and for testing various patches: https://lore.kernel.org/netdev/20220619003919.394622-1-i.maximets@ovn.org/ Note that I also added a missing xfrm4_policy_check() call, although this is probably not a big issue, as the SYN packet should have been dropped earlier. Fixes: b59c270104f0 ("[NETFILTER]: Keep conntrack reference until IPsec policy checks are done") Reported-by: Ilya Maximets <i.maximets@ovn.org> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Florian Westphal <fw@strlen.de> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Steffen Klassert <steffen.klassert@secunet.com> Tested-by: Ilya Maximets <i.maximets@ovn.org> Reviewed-by: Ilya Maximets <i.maximets@ovn.org> Link: https://lore.kernel.org/r/20220623050436.1290307-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-10net: add per_cpu_fw_alloc field to struct protoEric Dumazet
Each protocol having a ->memory_allocated pointer gets a corresponding per-cpu reserve, that following patches will use. Instead of having reserved bytes per socket, we want to have per-cpu reserves. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-30net: ipv4: Avoid bounds check warninghuhai
Fix the following build warning when CONFIG_IPV6 is not set: In function ‘fortify_memcpy_chk’, inlined from ‘tcp_md5_do_add’ at net/ipv4/tcp_ipv4.c:1210:2: ./include/linux/fortify-string.h:328:4: error: call to ‘__write_overflow_field’ declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning] 328 | __write_overflow_field(p_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Suggested-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: huhai <huhai@kylinos.cn> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20220526101213.2392980-1-zhanggenjian@kylinos.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
drivers/net/ethernet/mellanox/mlx5/core/main.c b33886971dbc ("net/mlx5: Initialize flow steering during driver probe") 40379a0084c2 ("net/mlx5_fpga: Drop INNOVA TLS support") f2b41b32cde8 ("net/mlx5: Remove ipsec_ops function table") https://lore.kernel.org/all/20220519040345.6yrjromcdistu7vh@sx1/ 16d42d313350 ("net/mlx5: Drain fw_reset when removing device") 8324a02c342a ("net/mlx5: Add exit route when waiting for FW") https://lore.kernel.org/all/20220519114119.060ce014@canb.auug.org.au/ tools/testing/selftests/net/mptcp/mptcp_join.sh e274f7154008 ("selftests: mptcp: add subflow limits test-cases") b6e074e171bc ("selftests: mptcp: add infinite map testcase") 5ac1d2d63451 ("selftests: mptcp: Add tests for userspace PM type") https://lore.kernel.org/all/20220516111918.366d747f@canb.auug.org.au/ net/mptcp/options.c ba2c89e0ea74 ("mptcp: fix checksum byte order") 1e39e5a32ad7 ("mptcp: infinite mapping sending") ea66758c1795 ("tcp: allow MPTCP to update the announced window") https://lore.kernel.org/all/20220519115146.751c3a37@canb.auug.org.au/ net/mptcp/pm.c 95d686517884 ("mptcp: fix subflow accounting on close") 4d25247d3ae4 ("mptcp: bypass in-kernel PM restrictions for non-kernel PMs") https://lore.kernel.org/all/20220516111435.72f35dca@canb.auug.org.au/ net/mptcp/subflow.c ae66fb2ba6c3 ("mptcp: Do TCP fallback on early DSS checksum failure") 0348c690ed37 ("mptcp: add the fallback check") f8d4bcacff3b ("mptcp: infinite mapping receiving") https://lore.kernel.org/all/20220519115837.380bb8d4@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-16net: tcp: reset 'drop_reason' to NOT_SPCIFIED in tcp_v{4,6}_rcv()Menglong Dong
The 'drop_reason' that passed to kfree_skb_reason() in tcp_v4_rcv() and tcp_v6_rcv() can be SKB_NOT_DROPPED_YET(0), as it is used as the return value of tcp_inbound_md5_hash(). And it can panic the kernel with NULL pointer in net_dm_packet_report_size() if the reason is 0, as drop_reasons[0] is NULL. Fixes: 1330b6ef3313 ("skb: make drop reason booleanable") Reviewed-by: Jiang Biao <benbjiang@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-13Revert "tcp/dccp: get rid of inet_twsk_purge()"Eric Dumazet
This reverts commits: 0dad4087a86a2cbe177404dc73f18ada26a2c390 ("tcp/dccp: get rid of inet_twsk_purge()") d507204d3c5cc57d9a8bdf0a477615bb59ea1611 ("tcp/dccp: add tw->tw_bslot") As Leonard pointed out, a newly allocated netns can happen to reuse a freed 'struct net'. While TCP TW timers were covered by my patches, other things were not: 1) Lookups in rx path (INET_MATCH() and INET6_MATCH()), as they look at 4-tuple plus the 'struct net' pointer. 2) /proc/net/tcp[6] and inet_diag, same reason. 3) hashinfo->bhash[], same reason. Fixing all this seems risky, lets instead revert. In the future, we might have a per netns tcp hash table, or a per netns list of timewait sockets... Fixes: 0dad4087a86a ("tcp/dccp: get rid of inet_twsk_purge()") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Leonard Crestez <cdleonard@gmail.com> Tested-by: Leonard Crestez <cdleonard@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-12net: inet: Retire port only listening_hashMartin KaFai Lau
The listen sk is currently stored in two hash tables, listening_hash (hashed by port) and lhash2 (hashed by port and address). After commit 0ee58dad5b06 ("net: tcp6: prefer listeners bound to an address") and commit d9fbc7f6431f ("net: tcp: prefer listeners bound to an address"), the TCP-SYN lookup fast path does not use listening_hash. The commit 05c0b35709c5 ("tcp: seq_file: Replace listening_hash with lhash2") also moved the seq_file (/proc/net/tcp) iteration usage from listening_hash to lhash2. There are still a few listening_hash usages left. One of them is inet_reuseport_add_sock() which uses the listening_hash to search a listen sk during the listen() system call. This turns out to be very slow on use cases that listen on many different VIPs at a popular port (e.g. 443). [ On top of the slowness in adding to the tail in the IPv6 case ]. The latter patch has a selftest to demonstrate this case. This patch takes this chance to move all remaining listening_hash usages to lhash2 and then retire listening_hash. Since most changes need to be done together, it is hard to cut the listening_hash to lhash2 switch into small patches. The changes in this patch is highlighted here for the review purpose. 1. Because of the listening_hash removal, lhash2 can use the sk->sk_nulls_node instead of the icsk->icsk_listen_portaddr_node. This will also keep the sk_unhashed() check to work as is after stop adding sk to listening_hash. The union is removed from inet_listen_hashbucket because only nulls_head is needed. 2. icsk->icsk_listen_portaddr_node and its helpers are removed. 3. The current lhash2 users needs to iterate with sk_nulls_node instead of icsk_listen_portaddr_node. One case is in the inet[6]_lhash2_lookup(). Another case is the seq_file iterator in tcp_ipv4.c. One thing to note is sk_nulls_next() is needed because the old inet_lhash2_for_each_icsk_continue() does a "next" first before iterating. 4. Move the remaining listening_hash usage to lhash2 inet_reuseport_add_sock() which this series is trying to improve. inet_diag.c and mptcp_diag.c are the final two remaining use cases and is moved to lhash2 now also. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-26net: generalize skb freeing deferral to per-cpu listsEric Dumazet
Logic added in commit f35f821935d8 ("tcp: defer skb freeing after socket lock is released") helped bulk TCP flows to move the cost of skbs frees outside of critical section where socket lock was held. But for RPC traffic, or hosts with RFS enabled, the solution is far from being ideal. For RPC traffic, recvmsg() has to return to user space right after skb payload has been consumed, meaning that BH handler has no chance to pick the skb before recvmsg() thread. This issue is more visible with BIG TCP, as more RPC fit one skb. For RFS, even if BH handler picks the skbs, they are still picked from the cpu on which user thread is running. Ideally, it is better to free the skbs (and associated page frags) on the cpu that originally allocated them. This patch removes the per socket anchor (sk->defer_list) and instead uses a per-cpu list, which will hold more skbs per round. This new per-cpu list is drained at the end of net_action_rx(), after incoming packets have been processed, to lower latencies. In normal conditions, skbs are added to the per-cpu list with no further action. In the (unlikely) cases where the cpu does not run net_action_rx() handler fast enough, we use an IPI to raise NET_RX_SOFTIRQ on the remote cpu. Also, we do not bother draining the per-cpu list from dev_cpu_dead() This is because skbs in this list have no requirement on how fast they should be freed. Note that we can add in the future a small per-cpu cache if we see any contention on sd->defer_lock. Tested on a pair of hosts with 100Gbit NIC, RFS enabled, and /proc/sys/net/ipv4/tcp_rmem[2] tuned to 16MB to work around page recycling strategy used by NIC driver (its page pool capacity being too small compared to number of skbs/pages held in sockets receive queues) Note that this tuning was only done to demonstrate worse conditions for skb freeing for this particular test. These conditions can happen in more general production workload. 10 runs of one TCP_STREAM flow Before: Average throughput: 49685 Mbit. Kernel profiles on cpu running user thread recvmsg() show high cost for skb freeing related functions (*) 57.81% [kernel] [k] copy_user_enhanced_fast_string (*) 12.87% [kernel] [k] skb_release_data (*) 4.25% [kernel] [k] __free_one_page (*) 3.57% [kernel] [k] __list_del_entry_valid 1.85% [kernel] [k] __netif_receive_skb_core 1.60% [kernel] [k] __skb_datagram_iter (*) 1.59% [kernel] [k] free_unref_page_commit (*) 1.16% [kernel] [k] __slab_free 1.16% [kernel] [k] _copy_to_iter (*) 1.01% [kernel] [k] kfree (*) 0.88% [kernel] [k] free_unref_page 0.57% [kernel] [k] ip6_rcv_core 0.55% [kernel] [k] ip6t_do_table 0.54% [kernel] [k] flush_smp_call_function_queue (*) 0.54% [kernel] [k] free_pcppages_bulk 0.51% [kernel] [k] llist_reverse_order 0.38% [kernel] [k] process_backlog (*) 0.38% [kernel] [k] free_pcp_prepare 0.37% [kernel] [k] tcp_recvmsg_locked (*) 0.37% [kernel] [k] __list_add_valid 0.34% [kernel] [k] sock_rfree 0.34% [kernel] [k] _raw_spin_lock_irq (*) 0.33% [kernel] [k] __page_cache_release 0.33% [kernel] [k] tcp_v6_rcv (*) 0.33% [kernel] [k] __put_page (*) 0.29% [kernel] [k] __mod_zone_page_state 0.27% [kernel] [k] _raw_spin_lock After patch: Average throughput: 73076 Mbit. Kernel profiles on cpu running user thread recvmsg() looks better: 81.35% [kernel] [k] copy_user_enhanced_fast_string 1.95% [kernel] [k] _copy_to_iter 1.95% [kernel] [k] __skb_datagram_iter 1.27% [kernel] [k] __netif_receive_skb_core 1.03% [kernel] [k] ip6t_do_table 0.60% [kernel] [k] sock_rfree 0.50% [kernel] [k] tcp_v6_rcv 0.47% [kernel] [k] ip6_rcv_core 0.45% [kernel] [k] read_tsc 0.44% [kernel] [k] _raw_spin_lock_irqsave 0.37% [kernel] [k] _raw_spin_lock 0.37% [kernel] [k] native_irq_return_iret 0.33% [kernel] [k] __inet6_lookup_established 0.31% [kernel] [k] ip6_protocol_deliver_rcu 0.29% [kernel] [k] tcp_rcv_established 0.29% [kernel] [k] llist_reverse_order v2: kdoc issue (kernel bots) do not defer if (alloc_cpu == smp_processor_id()) (Paolo) replace the sk_buff_head with a single-linked list (Jakub) add a READ_ONCE()/WRITE_ONCE() for the lockless read of sd->defer_list Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20220422201237.416238-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-22ipv4: Avoid using RTO_ONLINK with ip_route_connect().Guillaume Nault
Now that ip_rt_fix_tos() doesn't reset ->flowi4_scope unconditionally, we don't have to rely on the RTO_ONLINK bit to properly set the scope of a flowi4 structure. We can just set ->flowi4_scope explicitly and avoid using RTO_ONLINK in ->flowi4_tos. This patch converts callers of ip_route_connect(). Instead of setting the tos parameter with RT_CONN_FLAGS(sk), as all callers do, we can: 1- Drop the tos parameter from ip_route_connect(): its value was entirely based on sk, which is also passed as parameter. 2- Set ->flowi4_scope depending on the SOCK_LOCALROUTE socket option instead of always initialising it with RT_SCOPE_UNIVERSE (let's define ip_sock_rt_scope() for this purpose). 3- Avoid overloading ->flowi4_tos with RTO_ONLINK: since the scope is now properly initialised, we don't need to tell ip_rt_fix_tos() to adjust ->flowi4_scope for us. So let's define ip_sock_rt_tos(), which is the same as RT_CONN_FLAGS() but without the RTO_ONLINK bit overload. Note: In the original ip_route_connect() code, __ip_route_output_key() might clear the RTO_ONLINK bit of fl4->flowi4_tos (because of ip_rt_fix_tos()). Therefore flowi4_update_output() had to reuse the original tos variable. Now that we don't set RTO_ONLINK any more, this is not a problem and we can use fl4->flowi4_tos in flowi4_update_output(). Signed-off-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-06tcp: add accessors to read/set tp->snd_cwndEric Dumazet
We had various bugs over the years with code breaking the assumption that tp->snd_cwnd is greater than zero. Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction") can trigger, and without a repro we would have to spend considerable time finding the bug. Instead of complaining too late, we want to catch where and when tp->snd_cwnd is set to an illegal value. Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Link: https://lore.kernel.org/r/20220405233538.947344-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-09tcp: adjust TSO packet sizes based on min_rttEric Dumazet
Back when tcp_tso_autosize() and TCP pacing were introduced, our focus was really to reduce burst sizes for long distance flows. The simple heuristic of using sk_pacing_rate/1024 has worked well, but can lead to too small packets for hosts in the same rack/cluster, when thousands of flows compete for the bottleneck. Neal Cardwell had the idea of making the TSO burst size a function of both sk_pacing_rate and tcp_min_rtt() Indeed, for local flows, sending bigger bursts is better to reduce cpu costs, as occasional losses can be repaired quite fast. This patch is based on Neal Cardwell implementation done more than two years ago. bbr is adjusting max_pacing_rate based on measured bandwidth, while cubic would over estimate max_pacing_rate. /proc/sys/net/ipv4/tcp_tso_rtt_log can be used to tune or disable this new feature, in logarithmic steps. Tested: 100Gbit NIC, two hosts in the same rack, 4K MTU. 600 flows rate-limited to 20000000 bytes per second. Before patch: (TSO sizes would be limited to 20000000/1024/4096 -> 4 segments per TSO) ~# echo 0 >/proc/sys/net/ipv4/tcp_tso_rtt_log ~# nstat -n;perf stat ./super_netperf 600 -H otrv6 -l 20 -- -K dctcp -q 20000000;nstat|egrep "TcpInSegs|TcpOutSegs|TcpRetransSegs|Delivered" 96005 Performance counter stats for './super_netperf 600 -H otrv6 -l 20 -- -K dctcp -q 20000000': 65,945.29 msec task-clock # 2.845 CPUs utilized 1,314,632 context-switches # 19935.279 M/sec 5,292 cpu-migrations # 80.249 M/sec 940,641 page-faults # 14264.023 M/sec 201,117,030,926 cycles # 3049769.216 GHz (83.45%) 17,699,435,405 stalled-cycles-frontend # 8.80% frontend cycles idle (83.48%) 136,584,015,071 stalled-cycles-backend # 67.91% backend cycles idle (83.44%) 53,809,530,436 instructions # 0.27 insn per cycle # 2.54 stalled cycles per insn (83.36%) 9,062,315,523 branches # 137422329.563 M/sec (83.22%) 153,008,621 branch-misses # 1.69% of all branches (83.32%) 23.182970846 seconds time elapsed TcpInSegs 15648792 0.0 TcpOutSegs 58659110 0.0 # Average of 3.7 4K segments per TSO packet TcpExtTCPDelivered 58654791 0.0 TcpExtTCPDeliveredCE 19 0.0 After patch: ~# echo 9 >/proc/sys/net/ipv4/tcp_tso_rtt_log ~# nstat -n;perf stat ./super_netperf 600 -H otrv6 -l 20 -- -K dctcp -q 20000000;nstat|egrep "TcpInSegs|TcpOutSegs|TcpRetransSegs|Delivered" 96046 Performance counter stats for './super_netperf 600 -H otrv6 -l 20 -- -K dctcp -q 20000000': 48,982.58 msec task-clock # 2.104 CPUs utilized 186,014 context-switches # 3797.599 M/sec 3,109 cpu-migrations # 63.472 M/sec 941,180 page-faults # 19214.814 M/sec 153,459,763,868 cycles # 3132982.807 GHz (83.56%) 12,069,861,356 stalled-cycles-frontend # 7.87% frontend cycles idle (83.32%) 120,485,917,953 stalled-cycles-backend # 78.51% backend cycles idle (83.24%) 36,803,672,106 instructions # 0.24 insn per cycle # 3.27 stalled cycles per insn (83.18%) 5,947,266,275 branches # 121417383.427 M/sec (83.64%) 87,984,616 branch-misses # 1.48% of all branches (83.43%) 23.281200256 seconds time elapsed TcpInSegs 1434706 0.0 TcpOutSegs 58883378 0.0 # Average of 41 4K segments per TSO packet TcpExtTCPDelivered 58878971 0.0 TcpExtTCPDeliveredCE 9664 0.0 Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://lore.kernel.org/r/20220309015757.2532973-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-09skb: make drop reason booleanableJakub Kicinski
We have a number of cases where function returns drop/no drop decision as a boolean. Now that we want to report the reason code as well we have to pass extra output arguments. We can make the reason code evaluate correctly as bool. I believe we're good to reorder the reasons as they are reported to user space as strings. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-24net/tcp: Merge TCP-MD5 inbound callbacksDmitry Safonov
The functions do essentially the same work to verify TCP-MD5 sign. Code can be merged into one family-independent function in order to reduce copy'n'paste and generated code. Later with TCP-AO option added, this will allow to create one function that's responsible for segment verification, that will have all the different checks for MD5/AO/non-signed packets, which in turn will help to see checks for all corner-cases in one function, rather than spread around different families and functions. Cc: Eric Dumazet <edumazet@google.com> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Signed-off-by: Dmitry Safonov <dima@arista.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20220223175740.452397-1-dima@arista.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-20net: tcp: use kfree_skb_reason() for tcp_v{4,6}_do_rcv()Menglong Dong
Replace kfree_skb() used in tcp_v4_do_rcv() and tcp_v6_do_rcv() with kfree_skb_reason(). Reviewed-by: Mengen Sun <mengensun@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-20net: tcp: add skb drop reasons to tcp_add_backlog()Menglong Dong
Pass the address of drop_reason to tcp_add_backlog() to store the reasons for skb drops when fails. Following drop reasons are introduced: SKB_DROP_REASON_SOCKET_BACKLOG Reviewed-by: Mengen Sun <mengensun@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-20net: tcp: add skb drop reasons to tcp_v{4,6}_inbound_md5_hash()Menglong Dong
Pass the address of drop reason to tcp_v4_inbound_md5_hash() and tcp_v6_inbound_md5_hash() to store the reasons for skb drops when this function fails. Therefore, the drop reason can be passed to kfree_skb_reason() when the skb needs to be freed. Following drop reasons are added: SKB_DROP_REASON_TCP_MD5NOTFOUND SKB_DROP_REASON_TCP_MD5UNEXPECTED SKB_DROP_REASON_TCP_MD5FAILURE SKB_DROP_REASON_TCP_MD5* above correspond to LINUX_MIB_TCPMD5* Reviewed-by: Mengen Sun <mengensun@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-20net: tcp: add skb drop reasons to tcp_v4_rcv()Menglong Dong
Use kfree_skb_reason() for some path in tcp_v4_rcv() that missed before, including: SKB_DROP_REASON_SOCKET_FILTER SKB_DROP_REASON_XFRM_POLICY Reviewed-by: Mengen Sun <mengensun@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-27Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-27Merge tag 'net-5.17-rc2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Jakub Kicinski: "Including fixes from netfilter and can. Current release - new code bugs: - tcp: add a missing sk_defer_free_flush() in tcp_splice_read() - tcp: add a stub for sk_defer_free_flush(), fix CONFIG_INET=n - nf_tables: set last expression in register tracking area - nft_connlimit: fix memleak if nf_ct_netns_get() fails - mptcp: fix removing ids bitmap setting - bonding: use rcu_dereference_rtnl when getting active slave - fix three cases of sleep in atomic context in drivers: lan966x, gve - handful of build fixes for esoteric drivers after netdev->dev_addr was made const Previous releases - regressions: - revert "ipv6: Honor all IPv6 PIO Valid Lifetime values", it broke Linux compatibility with USGv6 tests - procfs: show net device bound packet types - ipv4: fix ip option filtering for locally generated fragments - phy: broadcom: hook up soft_reset for BCM54616S Previous releases - always broken: - ipv4: raw: lock the socket in raw_bind() - ipv4: decrease the use of shared IPID generator to decrease the chance of attackers guessing the values - procfs: fix cross-netns information leakage in /proc/net/ptype - ethtool: fix link extended state for big endian - bridge: vlan: fix single net device option dumping - ping: fix the sk_bound_dev_if match in ping_lookup" * tag 'net-5.17-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (86 commits) net: bridge: vlan: fix memory leak in __allowed_ingress net: socket: rename SKB_DROP_REASON_SOCKET_FILTER ipv4: remove sparse error in ip_neigh_gw4() ipv4: avoid using shared IP generator for connected sockets ipv4: tcp: send zero IPID in SYNACK messages ipv4: raw: lock the socket in raw_bind() MAINTAINERS: add missing IPv4/IPv6 header paths MAINTAINERS: add more files to eth PHY net: stmmac: dwmac-sun8i: use return val of readl_poll_timeout() net: bridge: vlan: fix single net device option dumping net: stmmac: skip only stmmac_ptp_register when resume from suspend net: stmmac: configure PTP clock source prior to PTP initialization Revert "ipv6: Honor all IPv6 PIO Valid Lifetime values" connector/cn_proc: Use task_is_in_init_pid_ns() pid: Introduce helper task_is_in_init_pid_ns() gve: Fix GFP flags when allocing pages net: lan966x: Fix sleep in atomic context when updating MAC table net: lan966x: Fix sleep in atomic context when injecting frames ethernet: seeq/ether3: don't write directly to netdev->dev_addr ethernet: 8390/etherh: don't write directly to netdev->dev_addr ...
2022-01-27net: socket: rename SKB_DROP_REASON_SOCKET_FILTERMenglong Dong
Rename SKB_DROP_REASON_SOCKET_FILTER, which is used as the reason of skb drop out of socket filter before it's part of a released kernel. It will be used for more protocols than just TCP in future series. Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/all/20220127091308.91401-2-imagedong@tencent.com/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-26tcp: allocate tcp_death_row outside of struct netns_ipv4Eric Dumazet
I forgot tcp had per netns tracking of timewait sockets, and their sysctl to change the limit. After 0dad4087a86a ("tcp/dccp: get rid of inet_twsk_purge()"), whole struct net can be freed before last tw socket is freed. We need to allocate a separate struct inet_timewait_death_row object per netns. tw_count becomes a refcount and gains associated debugging infrastructure. BUG: KASAN: use-after-free in inet_twsk_kill+0x358/0x3c0 net/ipv4/inet_timewait_sock.c:46 Read of size 8 at addr ffff88807d5f9f40 by task kworker/1:7/3690 CPU: 1 PID: 3690 Comm: kworker/1:7 Not tainted 5.16.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events pwq_unbound_release_workfn Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold+0x83/0xdf mm/kasan/report.c:459 inet_twsk_kill+0x358/0x3c0 net/ipv4/inet_timewait_sock.c:46 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lockdep_unregister_key+0x1c9/0x250 kernel/locking/lockdep.c:6328 Code: 00 00 00 48 89 ee e8 46 fd ff ff 4c 89 f7 e8 5e c9 ff ff e8 09 cc ff ff 9c 58 f6 c4 02 75 26 41 f7 c4 00 02 00 00 74 01 fb 5b <5d> 41 5c 41 5d 41 5e 41 5f e9 19 4a 08 00 0f 0b 5b 5d 41 5c 41 5d RSP: 0018:ffffc90004077cb8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffff88807b61b498 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888077027128 R08: 0000000000000001 R09: ffffffff8f1ea4fc R10: fffffbfff1ff93ee R11: 000000000000af1e R12: 0000000000000246 R13: 0000000000000000 R14: ffffffff8ffc89b8 R15: ffffffff90157fb0 wq_unregister_lockdep kernel/workqueue.c:3508 [inline] pwq_unbound_release_workfn+0x254/0x340 kernel/workqueue.c:3746 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> Allocated by task 3635: kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:437 [inline] __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:470 kasan_slab_alloc include/linux/kasan.h:260 [inline] slab_post_alloc_hook mm/slab.h:732 [inline] slab_alloc_node mm/slub.c:3230 [inline] slab_alloc mm/slub.c:3238 [inline] kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3243 kmem_cache_zalloc include/linux/slab.h:705 [inline] net_alloc net/core/net_namespace.c:407 [inline] copy_net_ns+0x125/0x760 net/core/net_namespace.c:462 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3048 __do_sys_unshare kernel/fork.c:3119 [inline] __se_sys_unshare kernel/fork.c:3117 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3117 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The buggy address belongs to the object at ffff88807d5f9a80 which belongs to the cache net_namespace of size 6528 The buggy address is located 1216 bytes inside of 6528-byte region [ffff88807d5f9a80, ffff88807d5fb400) The buggy address belongs to the page: page:ffffea0001f57e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88807d5f9a80 pfn:0x7d5f8 head:ffffea0001f57e00 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff888070023001 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffff888010dd4f48 ffffea0001404e08 ffff8880118fd000 raw: ffff88807d5f9a80 0000000000040002 00000001ffffffff ffff888070023001 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3634, ts 119694798460, free_ts 119693556950 prep_new_page mm/page_alloc.c:2434 [inline] get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab mm/slub.c:1944 [inline] new_slab+0x28a/0x3b0 mm/slub.c:2004 ___slab_alloc+0x87c/0xe90 mm/slub.c:3018 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105 slab_alloc_node mm/slub.c:3196 [inline] slab_alloc mm/slub.c:3238 [inline] kmem_cache_alloc+0x35c/0x3a0 mm/slub.c:3243 kmem_cache_zalloc include/linux/slab.h:705 [inline] net_alloc net/core/net_namespace.c:407 [inline] copy_net_ns+0x125/0x760 net/core/net_namespace.c:462 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3048 __do_sys_unshare kernel/fork.c:3119 [inline] __se_sys_unshare kernel/fork.c:3117 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3117 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1352 [inline] free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404 free_unref_page_prepare mm/page_alloc.c:3325 [inline] free_unref_page+0x19/0x690 mm/page_alloc.c:3404 skb_free_head net/core/skbuff.c:655 [inline] skb_release_data+0x65d/0x790 net/core/skbuff.c:677 skb_release_all net/core/skbuff.c:742 [inline] __kfree_skb net/core/skbuff.c:756 [inline] consume_skb net/core/skbuff.c:914 [inline] consume_skb+0xc2/0x160 net/core/skbuff.c:908 skb_free_datagram+0x1b/0x1f0 net/core/datagram.c:325 netlink_recvmsg+0x636/0xea0 net/netlink/af_netlink.c:1998 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] sock_recvmsg net/socket.c:962 [inline] ____sys_recvmsg+0x2c4/0x600 net/socket.c:2632 ___sys_recvmsg+0x127/0x200 net/socket.c:2674 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2704 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Memory state around the buggy address: ffff88807d5f9e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807d5f9e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807d5f9f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807d5f9f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807d5fa000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb Fixes: 0dad4087a86a ("tcp/dccp: get rid of inet_twsk_purge()") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Reported-by: Paolo Abeni <pabeni@redhat.com> Tested-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20220126180714.845362-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-25ipv4/tcp: do not use per netns ctl socketsEric Dumazet
TCP ipv4 uses per-cpu/per-netns ctl sockets in order to send RST and some ACK packets (on behalf of TIMEWAIT sockets). This adds memory and cpu costs, which do not seem needed. Now typical servers have 256 or more cores, this adds considerable tax to netns users. tcp sockets are used from BH context, are not receiving packets, and do not store any persistent state but the 'struct net' pointer in order to be able to use IPv4 output functions. Note that I attempted a related change in the past, that had to be hot-fixed in commit bdbbb8527b6f ("ipv4: tcp: get rid of ugly unicast_sock") This patch could very well surface old bugs, on layers not taking care of sk->sk_kern_sock properly. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>