net-tcp: retire TFO_SERVER_WO_SOCKOPT2 config (cebc5cba) · Commits · 戴 / test

Documentation/networking/ip-sysctl.txt

+23 −22

Original line number	Original line	Diff line number	Diff line
	@@ -575,32 +575,33 @@ tcp_syncookies - BOOLEAN
	unconditionally generation of syncookies.		unconditionally generation of syncookies.

	tcp_fastopen - INTEGER		tcp_fastopen - INTEGER
	Enable TCP Fast Open feature (draft-ietf-tcpm-fastopen) to send data		Enable TCP Fast Open (RFC7413) to send and accept data in the opening
	in the opening SYN packet. To use this feature, the client application		SYN packet.
	must use sendmsg() or sendto() with MSG_FASTOPEN flag rather than
	connect() to perform a TCP handshake automatically.

	The values (bitmap) are		The client support is enabled by flag 0x1 (on by default). The client
	1: Enables sending data in the opening SYN on the client w/ MSG_FASTOPEN.		then must use sendmsg() or sendto() with the MSG_FASTOPEN flag,
	2: Enables TCP Fast Open on the server side, i.e., allowing data in		rather than connect() to send data in SYN.
	a SYN packet to be accepted and passed to the application before
	3-way hand shake finishes.
	4: Send data in the opening SYN regardless of cookie availability and
	without a cookie option.
	0x100: Accept SYN data w/o validating the cookie.
	0x200: Accept data-in-SYN w/o any cookie option present.
	0x400/0x800: Enable Fast Open on all listeners regardless of the
	TCP_FASTOPEN socket option. The two different flags designate two
	different ways of setting max_qlen without the TCP_FASTOPEN socket
	option.

	Default: 1		The server support is enabled by flag 0x2 (off by default). Then
			either enable for all listeners with another flag (0x400) or
			enable individual listeners via TCP_FASTOPEN socket option with
			the option value being the length of the syn-data backlog.

	Note that the client & server side Fast Open flags (1 and 2		The values (bitmap) are
	respectively) must be also enabled before the rest of flags can take		0x1: (client) enables sending data in the opening SYN on the client.
	effect.		0x2: (server) enables the server support, i.e., allowing data in
			a SYN packet to be accepted and passed to the
			application before 3-way handshake finishes.
			0x4: (client) send data in the opening SYN regardless of cookie
			availability and without a cookie option.
			0x200: (server) accept data-in-SYN w/o any cookie option present.
			0x400: (server) enable all listeners to support Fast Open by
			default without explicit TCP_FASTOPEN socket option.

			Default: 0x1

	See include/net/tcp.h and the code for more details.		Note that that additional client or server features are only
			effective if the basic support (0x1 and 0x2) are enabled respectively.

	tcp_syn_retries - INTEGER		tcp_syn_retries - INTEGER
	Number of times initial SYNs for an active TCP connection attempt		Number of times initial SYNs for an active TCP connection attempt

include/net/tcp.h

+1 −2

Original line number	Original line	Diff line number	Diff line
	@@ -227,10 +227,9 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
	#define TFO_SERVER_COOKIE_NOT_REQD 0x200		#define TFO_SERVER_COOKIE_NOT_REQD 0x200

	/* Force enable TFO on all listeners, i.e., not requiring the		/* Force enable TFO on all listeners, i.e., not requiring the
	* TCP_FASTOPEN socket option. SOCKOPT1/2 determine how to set max_qlen.		* TCP_FASTOPEN socket option.
	*/		*/
	#define TFO_SERVER_WO_SOCKOPT1 0x400		#define TFO_SERVER_WO_SOCKOPT1 0x400
	#define TFO_SERVER_WO_SOCKOPT2 0x800

	extern struct inet_timewait_death_row tcp_death_row;		extern struct inet_timewait_death_row tcp_death_row;

net/ipv4/af_inet.c

+8 −13

Original line number	Original line	Diff line number	Diff line
	@@ -211,24 +211,19 @@ int inet_listen(struct socket *sock, int backlog)
	* we can only allow the backlog to be adjusted.		* we can only allow the backlog to be adjusted.
	*/		*/
	if (old_state != TCP_LISTEN) {		if (old_state != TCP_LISTEN) {
	/* Check special setups for testing purpose to enable TFO w/o		/* Enable TFO w/o requiring TCP_FASTOPEN socket option.
	* requiring TCP_FASTOPEN sockopt.
	* Note that only TCP sockets (SOCK_STREAM) will reach here.		* Note that only TCP sockets (SOCK_STREAM) will reach here.
	* Also fastopenq may already been allocated because this		* Also fastopen backlog may already been set via the option
	* socket was in TCP_LISTEN state previously but was		* because the socket was in TCP_LISTEN state previously but
	* shutdown() (rather than close()).		* was shutdown() rather than close().
	*/		*/
	if ((sysctl_tcp_fastopen & TFO_SERVER_ENABLE) != 0 &&		if ((sysctl_tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) &&
			(sysctl_tcp_fastopen & TFO_SERVER_ENABLE) &&
	!inet_csk(sk)->icsk_accept_queue.fastopenq.max_qlen) {		!inet_csk(sk)->icsk_accept_queue.fastopenq.max_qlen) {
	if ((sysctl_tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) != 0)
	fastopen_queue_tune(sk, backlog);		fastopen_queue_tune(sk, backlog);
	else if ((sysctl_tcp_fastopen &
	TFO_SERVER_WO_SOCKOPT2) != 0)
	fastopen_queue_tune(sk,
	((uint)sysctl_tcp_fastopen) >> 16);

	tcp_fastopen_init_key_once(true);		tcp_fastopen_init_key_once(true);
	}		}

	err = inet_csk_listen_start(sk, backlog);		err = inet_csk_listen_start(sk, backlog);
	if (err)		if (err)
	goto out;		goto out;

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