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| author |   David S. Miller <davem@davemloft.net> | 2022-01-31 15:05:25 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-01-31 15:05:25 +0000 |
| commit | 01b2a995156d11166da00ce254d59bd7f7cefb92 (patch) | |
| tree | 7211b0a22e1a7011c1210fbfad9a0695f5a9bd93 /net/core/sock.c | |
| parent | selftests/net: timestamping: Fix bind_phc check (diff) | |
| parent | tcp: Change SYN ACK retransmit behaviour to account for rehash (diff) | |
| download | wireguard-linux-01b2a995156d11166da00ce254d59bd7f7cefb92.tar.xz wireguard-linux-01b2a995156d11166da00ce254d59bd7f7cefb92.zip | |
Merge branch 'hash-rethink'
Akhmat Karakotov says:
====================
Make hash rethink configurable
As it was shown in the report by Alexander Azimov, hash rethink at the
client-side may lead to connection timeout toward stateful anycast
services. Tom Herbert created a patchset to address this issue by applying
hash rethink only after a negative routing event (3RTOs) [1]. This change
also affects server-side behavior, which we found undesirable. This
patchset changes defaults in a way to make them safe: hash rethink at the
client-side is disabled and enabled at the server-side upon each RTO
event or in case of duplicate acknowledgments.
This patchset provides two options to change default behaviour. The hash
rethink may be disabled at the server-side by the new sysctl option.
Changes in the sysctl option don't affect default behavior at the
client-side.
Hash rethink can also be enabled/disabled with socket option or bpf
syscalls which ovewrite both default and sysctl settings. This socket
option is available on both client and server-side. This should provide
mechanics to enable hash rethink inside administrative domain, such as DC,
where hash rethink at the client-side can be desirable.
[1] https://lore.kernel.org/netdev/20210809185314.38187-1-tom@herbertland.com/
v2:
- Changed sysctl default to ENABLED in all patches. Reduced sysctl
and socket option size to u8. Fixed netns bug reported by kernel
test robot.
v3:
- Fixed bug with bad u8 comparison. Moved sk_txrehash to use less
bytes in struct. Added WRITE_ONCE() in setsockopt in and
READ_ONCE() in tcp_rtx_synack.
v4:
- Rebase and add documentation for sysctl option.
v5:
- Move sk_txrehash out of busy poll ifdef.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/sock.c')
| -rw-r--r-- | net/core/sock.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/net/core/sock.c b/net/core/sock.c index cccf21f3618d..d6804685f17f 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1447,6 +1447,15 @@ set_sndbuf: break; } + case SO_TXREHASH: + if (val < -1 || val > 1) { + ret = -EINVAL; + break; + } + /* Paired with READ_ONCE() in tcp_rtx_synack() */ + WRITE_ONCE(sk->sk_txrehash, (u8)val); + break; + default: ret = -ENOPROTOOPT; break; @@ -1834,6 +1843,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname, v.val = sk->sk_reserved_mem; break; + case SO_TXREHASH: + v.val = sk->sk_txrehash; + break; + default: /* We implement the SO_SNDLOWAT etc to not be settable * (1003.1g 7). @@ -3279,6 +3292,7 @@ void sock_init_data(struct socket *sock, struct sock *sk) sk->sk_pacing_rate = ~0UL; WRITE_ONCE(sk->sk_pacing_shift, 10); sk->sk_incoming_cpu = -1; + sk->sk_txrehash = SOCK_TXREHASH_DEFAULT; sk_rx_queue_clear(sk); /* |