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From: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
To: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	Neal Cardwell <ncardwell@google.com>,
	Yuchung Cheng <ycheng@google.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>
Cc: Benjamin Herrenschmidt <benh@amazon.com>,
	Kuniyuki Iwashima <kuniyu@amazon.co.jp>,
	Kuniyuki Iwashima <kuni1840@gmail.com>, <bpf@vger.kernel.org>,
	<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v8 bpf-next 01/11] net: Introduce net.ipv4.tcp_migrate_req.
Date: Sat, 12 Jun 2021 21:32:14 +0900	[thread overview]
Message-ID: <20210612123224.12525-2-kuniyu@amazon.co.jp> (raw)
In-Reply-To: <20210612123224.12525-1-kuniyu@amazon.co.jp>

This commit adds a new sysctl option: net.ipv4.tcp_migrate_req. If this
option is enabled or eBPF program is attached, we will be able to migrate
child sockets from a listener to another in the same reuseport group after
close() or shutdown() syscalls.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Reviewed-by: Benjamin Herrenschmidt <benh@amazon.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
---
 Documentation/networking/ip-sysctl.rst | 25 +++++++++++++++++++++++++
 include/net/netns/ipv4.h               |  1 +
 net/ipv4/sysctl_net_ipv4.c             |  9 +++++++++
 3 files changed, 35 insertions(+)

diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index a5c250044500..b0436d3a4f11 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -761,6 +761,31 @@ tcp_syncookies - INTEGER
 	network connections you can set this knob to 2 to enable
 	unconditionally generation of syncookies.
 
+tcp_migrate_req - BOOLEAN
+	The incoming connection is tied to a specific listening socket when
+	the initial SYN packet is received during the three-way handshake.
+	When a listener is closed, in-flight request sockets during the
+	handshake and established sockets in the accept queue are aborted.
+
+	If the listener has SO_REUSEPORT enabled, other listeners on the
+	same port should have been able to accept such connections. This
+	option makes it possible to migrate such child sockets to another
+	listener after close() or shutdown().
+
+	The BPF_SK_REUSEPORT_SELECT_OR_MIGRATE type of eBPF program should
+	usually be used to define the policy to pick an alive listener.
+	Otherwise, the kernel will randomly pick an alive listener only if
+	this option is enabled.
+
+	Note that migration between listeners with different settings may
+	crash applications. Let's say migration happens from listener A to
+	B, and only B has TCP_SAVE_SYN enabled. B cannot read SYN data from
+	the requests migrated from A. To avoid such a situation, cancel
+	migration by returning SK_DROP in the type of eBPF program, or
+	disable this option.
+
+	Default: 0
+
 tcp_fastopen - INTEGER
 	Enable TCP Fast Open (RFC7413) to send and accept data in the opening
 	SYN packet.
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 746c80cd4257..b8620519eace 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -126,6 +126,7 @@ struct netns_ipv4 {
 	u8 sysctl_tcp_syn_retries;
 	u8 sysctl_tcp_synack_retries;
 	u8 sysctl_tcp_syncookies;
+	u8 sysctl_tcp_migrate_req;
 	int sysctl_tcp_reordering;
 	u8 sysctl_tcp_retries1;
 	u8 sysctl_tcp_retries2;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 4fa77f182dcb..6f1e64d49232 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -960,6 +960,15 @@ static struct ctl_table ipv4_net_table[] = {
 		.proc_handler	= proc_dou8vec_minmax,
 	},
 #endif
+	{
+		.procname	= "tcp_migrate_req",
+		.data		= &init_net.ipv4.sysctl_tcp_migrate_req,
+		.maxlen		= sizeof(u8),
+		.mode		= 0644,
+		.proc_handler	= proc_dou8vec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE
+	},
 	{
 		.procname	= "tcp_reordering",
 		.data		= &init_net.ipv4.sysctl_tcp_reordering,
-- 
2.30.2


  reply	other threads:[~2021-06-12 12:33 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-12 12:32 [PATCH v8 bpf-next 00/11] Socket migration for SO_REUSEPORT Kuniyuki Iwashima
2021-06-12 12:32 ` Kuniyuki Iwashima [this message]
2021-06-12 12:32 ` [PATCH v8 bpf-next 02/11] tcp: Add num_closed_socks to struct sock_reuseport Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 03/11] tcp: Keep TCP_CLOSE sockets in the reuseport group Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 04/11] tcp: Add reuseport_migrate_sock() to select a new listener Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 05/11] tcp: Migrate TCP_ESTABLISHED/TCP_SYN_RECV sockets in accept queues Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 06/11] tcp: Migrate TCP_NEW_SYN_RECV requests at retransmitting SYN+ACKs Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 07/11] tcp: Migrate TCP_NEW_SYN_RECV requests at receiving the final ACK Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 08/11] bpf: Support BPF_FUNC_get_socket_cookie() for BPF_PROG_TYPE_SK_REUSEPORT Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 09/11] bpf: Support socket migration by eBPF Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 10/11] libbpf: Set expected_attach_type for BPF_PROG_TYPE_SK_REUSEPORT Kuniyuki Iwashima
2021-06-12 12:32 ` [PATCH v8 bpf-next 11/11] bpf: Test BPF_SK_REUSEPORT_SELECT_OR_MIGRATE Kuniyuki Iwashima
2021-06-15 15:35 ` [PATCH v8 bpf-next 00/11] Socket migration for SO_REUSEPORT Eric Dumazet
2021-06-15 16:03   ` Kuniyuki Iwashima
2021-06-15 16:19     ` Daniel Borkmann

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